REVIEW
published: 10 April 2017
doi: 10.3389/fonc.2017.00060
The Mitochondrial VoltageDependent Anion Channel 1, Ca2+
Transport, Apoptosis, and Their
Regulation
Varda Shoshan-Barmatz*, Soumasree De and Alon Meir
Department of Life Sciences, National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev,
Beer-Sheva, Israel
Edited by:
Paolo Pinton,
University of Ferrara, Italy
Reviewed by:
Ildikò Szabò,
University of Padua, Italy
Catherine Brenner Jan,
Institut national de la santé
et de la recherche médicale
(INSERM), France
*Correspondence:
Varda Shoshan-Barmatz
vardasb@bgu.ac.il
Specialty section:
This article was submitted to
Molecular and Cellular Oncology,
a section of the journal
Frontiers in Oncology
Received: 20 December 2016
Accepted: 17 March 2017
Published: 10 April 2017
Citation:
Shoshan-Barmatz V, De S and
Meir A (2017) The Mitochondrial
Voltage-Dependent Anion
Channel 1, Ca2+ Transport,
Apoptosis, and Their Regulation.
Front. Oncol. 7:60.
doi: 10.3389/fonc.2017.00060
Frontiers in Oncology | www.frontiersin.org
In the outer mitochondrial membrane, the voltage-dependent anion channel 1 (VDAC1)
functions in cellular Ca2+ homeostasis by mediating the transport of Ca2+ in and out of
mitochondria. VDAC1 is highly Ca2+-permeable and modulates Ca2+ access to the mitochondrial intermembrane space. Intramitochondrial Ca2+ controls energy metabolism by
enhancing the rate of NADH production via modulating critical enzymes in the tricarboxylic acid cycle and fatty acid oxidation. Mitochondrial [Ca2+] is regarded as an important
determinant of cell sensitivity to apoptotic stimuli and was proposed to act as a “priming
signal,” sensitizing the organelle and promoting the release of pro-apoptotic proteins.
However, the precise mechanism by which intracellular Ca2+ ([Ca2+]i) mediates apoptosis
is not known. Here, we review the roles of VDAC1 in mitochondrial Ca2+ homeostasis
and in apoptosis. Accumulated evidence shows that apoptosis-inducing agents act by
increasing [Ca2+]i and that this, in turn, augments VDAC1 expression levels. Thus, a
new concept of how increased [Ca2+]i activates apoptosis is postulated. Specifically,
increased [Ca2+]i enhances VDAC1 expression levels, followed by VDAC1 oligomerization, cytochrome c release, and subsequently apoptosis. Evidence supporting this
new model suggesting that upregulation of VDAC1 expression constitutes a major
mechanism by which apoptotic stimuli induce apoptosis with VDAC1 oligomerization
being a molecular focal point in apoptosis regulation is presented. A new proposed
mechanism of pro-apoptotic drug action, namely Ca2+-dependent enhancement of
VDAC1 expression, provides a platform for developing a new class of anticancer drugs
modulating VDAC1 levels via the promoter and for overcoming the resistance of cancer
cells to chemotherapy.
Keywords: apoptosis, Ca2+ transporters, mitochondria, oligomerization, voltage-dependent anion channel
OVERVIEW
Intracellular Ca2+concentration ([Ca2+]i) regulates a number of cellular and intercellular events, such
as the cell cycle, proliferation, gene transcription, and cell death pathways, as well as processes like
muscle contractility and neuronal processing and transmission (1). The alteration of Ca2+ homeostasis is closely related with various cancer hallmarks, including proliferation, migration, angiogenesis,
invasion abilities, and resistance to cell death (2).
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VDAC1 in Ca2+ Signaling and Apoptosis
PATHWAYS MEDIATING Ca2+ FLUXES IN
THE MITOCHONDRIA
Various systems and mechanisms have evolved to control
and respond to minute changes in Ca2+ concentrations and
localization (3). Moreover, many cellular compartments
participate in the Ca2+ signaling network regulation. [Ca2+]i is
controlled via its transport in and out of the cell or/and in and
out of intracellular organelles. Within a given compartment,
[Ca2+] can be buffered by binding to specific proteins and other
molecules, as well as existing in its free form, albeit differentially
across compartments (1). The major organelles that participate
in controlling Ca2+ dynamics include the endoplasmic reticulum (ER) and mitochondria (4). Imbalance in the control of
[Ca2+]i can lead to mitochondria Ca2+ overload and ultimately,
to toxic effects. Tumor cells exhibit a well-developed capacity
for modulating cytosolic Ca2+ levels by remodeling the cellular
machinery that participates in processes that determine Ca2+
dynamics and homeostasis, as well as changes in sensitivity
to the induction of cell death. This review is focused on the
mitochondrial gatekeeper protein voltage-dependent anion
channel 1 (VDAC1) and its role in Ca2+ transport and on Ca2+mediated apoptosis involving regulation of VDAC1 expression
levels.
Ca
2+
Several mitochondria membrane proteins play central roles in
Ca2+ signaling and/or Ca2+ influx and efflux in normal and disease
conditions. Ca2+ transport across the IMM is mediated via several
proteins, including the mitochondrial Ca2+ uniporter (MCU) (23,
24) and the Na+/Ca2+ exchanger, NCLX, the major Ca2+ efflux
mediator (25, 26). In the OMM, VDAC1 was shown to control
Ca2+ permeability (27–30).
VDAC1, the Ca2+ Channel in the OMM
Three different isoforms of VDAC have been identified, VDAC1,
VDAC2, and VDAC3. VDAC1 has been best studied, whereas
only limited information regarding the cellular functions of
VDAC2 and VDAC3 is available (31). Thus, we focus here on
VDAC1.
VDAC1, a Multifunctional Channel, Controls Cell
Metabolism
VDAC1 at the OMM controls metabolic cross talk between mitochondria and rest of the cell by allowing the entry of metabolites
(pyruvate, malate, succinate, nucleotides, and NADH) into the
mitochondria and the exit of newly formed molecules, such as
hemes (32, 33) (Figure 1). VDAC1 is also involved in cholesterol
transport and mediates the fluxes of ions, including Ca2+ (34),
serves as a ROS transporter, and contributes to regulating the
redox states of mitochondria and the cytosol (32–34). Moreover,
VDAC1 at the OMM interacts with proteins that mediate and
regulate the integration of mitochondrial functions with other
cellular activities. VDAC1 forms a complex with adenine nucleotide translocase (ANT) and creatine kinase (35). The interaction
of VDAC1 with hexokinase (HK) allows for coupling between
OXPHOS and glycolysis, an important factor in cancer cell
energy homeostasis (the Warburg effect) (36). Thus, VDAC1
appears to be a convergence point for a variety of cell survival
and death signals, mediated through its association with various
ligands and proteins.
AND MITOCHONDRIA
Mitochondria not only play a key role in metabolism but also
serve as a major hub for cellular Ca2+ homeostasis, regulating
oxidative phosphorylation (OXPHOS) (4–7) and modulating
cytosolic Ca2+ signals (8, 9), cell death (10), and secretion (11,
12). Enclosed by two different membranes, namely the outer
mitochondrial membrane (OMM) and the inner mitochondrial
membrane (IMM), mitochondria thus present two aqueous
compartments, the intermembrane space (IMS) and the matrix
(M). To reach the matrix, Ca2+ must cross both the OMM and
the IMM. Indeed, the mitochondrial matrix is one of the major
cellular Ca2+ stores or buffers and is used to control [Ca2+]i and
dynamics. Within the mitochondrial matrix, Ca2+ is precipitated as insoluble CaPO4, which exists in equilibrium with free
Ca2+ (7, 13).
It is well established that mitochondria can rapidly sequester
large and sudden increases in [Ca2+]i at the expense of the membrane potential across the IMM that is generated by the electron
transport chain (6). Intramitochondrial Ca2+ controls energy
metabolism by enhancing the rate of NADH production via
modulating critical enzymes, such as those of the tricarboxylic
acid (TCA) cycle and fatty acid oxidation (14, 15), linking glycolysis to the TCA cycle (16). Indeed, matrix Ca2+ is an essential
cofactor for several rate-limiting TCA enzymes, namely pyruvate
dehydrogenase, isocitrate dehydrogenase, and α-ketoglutarate
dehydrogenase.
Mitochondrial Ca2+ ([Ca2+]m) homeostasis is important not
only for energy production but also for regulating [Ca2+]i and
activating cell apoptotic pathways (10, 17). Several recent reviews
have discussed the basic principles that govern [Ca2+]m homeostasis and maintenance of Ca2+ dynamics within organelles (18–22).
The OMM and IMM pathways allowing Ca2+ entry into and exit
from mitochondria are presented below.
Frontiers in Oncology | www.frontiersin.org
VDAC1 As Ca2+ Transporter at OMM
Found in the OMM, VDAC1 regulates the transport of Ca2+ in
and out of the mitochondria. VDAC1 is highly Ca2+-permeable
and modulates the accessibility of Ca2+ to the IMS (27–30)
(Figure 1). Bilayer-reconstituted VDAC1 under voltage-clamp
conditions and in the presence of different CaCl2 concentration gradients showed well-defined voltage-dependent channel
conductance as observed with either NaCl or KCl solution (27,
29). Bilayer-reconstituted VDAC1 showed higher permeability to
Ca2+ in the low conductance state (29). The Ca2+ permeability of
VDAC1 has also been established upon VDAC1 reconstitution
into liposomes (27).
Various studies support the function of VDAC1 in the
transport of Ca2+ and in cellular Ca2+ homeostasis. VDAC1
overexpression increases [Ca2+]m concentration in HeLa cells and
skeletal myotubes (37), and silencing of VDAC1 expression by
2
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VDAC1 in Ca2+ Signaling and Apoptosis
FIGURE 1 | Schematic representation of voltage-dependent anion channel 1 (VDAC1) as a multifunctional protein involved in Ca2+ and metabolite
transport, energy production, and the structural and functional association of mitochondria with the endoplasmic reticulum (ER). The various
functions of VDAC1 in cell and mitochondria functions are presented. These include (A) Ca2+ signaling by transporting Ca2+; (B) control of metabolic cross talk
between the mitochondria and the rest of the cell; (C) mediating cellular energy production by transporting ATP/ADP, NADH, and acyl-CoA from the cytosol to the
intermembrane space and regulating glycolysis via the association with hexokinase (HK); (D) involvement in structural and functional association with the ER,
mediating Ca2+ transport from the ER to mitochondria; (E) participation in apoptosis via its oligomerization to form a protein-conducting channel within a VDAC1
homo-oligomer, allowing Cyto c release and apoptotic cell death. Ca2+ influx and efflux transport systems in the outer mitochondrial membrane (OMM) and IMM are
shown. In the OMM, VDAC1 is presented as a Ca2+ channel and also functions in the transport of Mg2+. In the IMM, Ca2+ uptake into the matrix is mediated by a
Ca2+-selective transporter, the mitochondrial Ca2+ uniporter (MCU), regulated by a calcium-sensing accessory subunit (MCU1). Ryanodine receptor (RyR) in the IMM
mediates Ca2+ influx. Ca2+ efflux is mediated by NCLX, an Na+/Ca2+ exchanger. High levels of matrix Ca2+ accumulation trigger the opening of the PTP, a fast Ca2+
release channel. The function of Ca2+ in regulation of energy production is mediated via tricarboxylic acid (TCA) cycle regulation. This includes activation of pyruvate
dehydrogenase (PDH), isocitrate dehydrogenase (ICDH), and α-ketoglutarate dehydrogenase (αKGDH) by intramitochondrial Ca2+, leading to enhanced activity of
the TCA cycle. The electron transport chain (ETC) and the ATP synthase (FoF1) are also presented. Molecular fluxes are indicated by arrows. VDAC1 mediates the
transfer of fatty acid acyl-CoAs across the OMM to the IMS, where they are converted into acylcarnitine by CPT1a for further processing by β-oxidation. VDAC1 is
involved in cholesterol transport by being constituent of a multi-protein complex, the transduceosome, containing Star/TSPO/VDAC1. The ER associated with the
mitochondria is presented with key proteins indicated. These include the inositol 3 phosphate receptor type 3 (IP3R3), the sigma1 receptor (Sig1R) (a reticular
chaperone), binding immunoglobulin protein (BiP), the ER heat shock protein (HSP70) chaperone, and glucose-regulated protein 75 (GRP75). IP3 activates the IP3R
in the ER to release Ca2+ that is directly transferred to the mitochondrion via VDAC1.
siRNA attenuates [Ca2+]m uptake and cell apoptosis induced by
H2O2 or ceramide (38). It was also proposed that the magnitude
of Ca2+ transfer into the mitochondrial matrix is regulated by
protein–protein interactions between Bcl-xL and VDAC1 or
VDAC3, with this interaction promoting matrix Ca2+ accumulation by increasing Ca2+ transfer across the OMM (39).
Frontiers in Oncology | www.frontiersin.org
Silencing each of the VDAC isoforms in the presence of a proapoptotic stimulus revealed that each was differentially sensitive
to H2O2, with VDAC1 silencing potentiating H2O2-induced apoptosis and impairing [Ca2+]m loading, while VDAC2 silencing had
the opposite effects (38). In addition, several VDAC-interacting
molecules like 4,4′-diisothiocyanostilbene-2,2′-disulfonic acid
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VDAC1 in Ca2+ Signaling and Apoptosis
(DIDS), 4-acetamido-4′-isothiocyanato-stilbene-2,2′-disulfonic
acid, and dinitrostilbene-2,2′-disulfonic acid were shown to prevent apoptosis and also inhibit the rise in [Ca2+] levels associated
with apoptosis induction (40). In another example, 5-aminolevulinic precluded Ca2+-mediated oxidative stress and apoptosis
through VDAC1 inhibition (41).
and it was suggested that impaired communication between
the L-type Ca2+ channel and mitochondrial VDAC contributes
to cardiomyopathy (60). Thus, such interactions of VDAC with
proteins associated with Ca2+ transport or activated by Ca2+ point
to VDAC as functioning not only in [Ca2+]i homeostasis but also
in many Ca2+-regulated cellular activities.
VDAC1 Possesses Ca2+-Binding Sites
VDAC1 Function in Mitochondria—ER/Sarcoplasmic
Reticulum (SR) Ca2+-Cross Talk
Several lines of evidence suggest that VDAC1 possesses divalent
cation-binding site(s). [Ca2+], at micromolar concentrations,
switched VDAC1 from a low to high conductance state (30).
The trivalent ions La3+ and Tb3+, known to bind to Ca2+-binding
proteins (42), reduced the channel conductance of bilayer-reconstituted VDAC (43). This and the direct demonstration of Tb3+
binding to purified VDAC1, as reflected in an enhanced green
fluorescence, further suggest that VDAC1 possesses divalent
cation-binding site(s) that its occupation by La3+ or Tb3+ lead to
reduced channel conductance.
Similarly, molecules known to specifically interact with several Ca2+-binding proteins like ruthenium red (RuR) (43) and
ruthenium amine binuclear complex (Ru360) (44), as well as a
photo-reactive analog, azido ruthenium (AzRu) (45), induced
VDAC1 channel closure in a time-dependent manner and stabilized the channel in a low conducting state. These compounds
also inhibited apoptosis (43–45).
The putative VDAC1 metal binding site for RuR and AzRu was
analyzed by mutation of specific VDAC1 residues (43). It has been
demonstrated that E72 and E202 are essential for RuR-mediated
reduction of bilayer-reconstituted VDAC1 conductance and for
RuR-mediated protection against VDAC1-induced cell death
(43, 46). This suggests that these two glutamate residues, located
in two different β-strands, may form the VDAC1 Ca2+-binding
site(s), or part thereof. However, their distant location and their
being located in transmembrane sequences, suggest that these
residues may stabilize VDAC1 in a conformation that is recognized by RuR and AzRu. Thus, these Ru-containing molecules
may bind to a non-defined site in VDAC1 to induce conformation changes leading to reduced conductance and inhibited
apoptosis.
The competition between Ca2+ and RuR (43), as well as the
demonstration of VDAC gating regulation by physiological levels
of Ca2+, whereby Ca2+ increases the conductance of the VDAC1
channel (30), supports the physiological function of the VDAC1
Ca2+-binding site(s).
The participation of VDAC1 in supramolecular complexes and
intracellular communication, including Ca2+ signal delivery
between the ER and mitochondria, was postulated over a decade
ago (28, 61, 62). The components involved in ER–mitochondria
interaction include the IP3 receptor and grp75 on the ER as tethering components and VDAC1 on the OMM (63). VDAC1 (but
not VDAC2 or VDAC3) was found to provide the route for Ca2+
entry into mitochondria upon apoptotic stimulus, representing
a fundamental factor in mitochondria physiology (38). It was,
moreover, proposed that the magnitude of Ca2+ transfer from
the ER into the mitochondrial matrix is regulated by Bcl-xL (39,
51). ER–mitochondria cross talk regulates not only Ca2+ transfer
but also different processes, such as mitochondrial fission,
autophagy, and inflammation (64). Finally, Ca2+ dynamics are
greatly enhanced where there is close apposition of the ER with
mitochondria, as compared to the bulk cytosol. Such changes in
Ca2+ signal profiles were modified by ROS, as monitored with
genetically encoded redox indicators (65).
MCU and Auxiliary Subunits Form a
Selective Ca2+ Transporter in the IMM
Ca2+ transport across the IMM and into the matrix is mediated
via the MCU (23, 24), with the driving force being the steep
mitochondrial membrane potential (8, 66, 67) (Figure 1). Such
delivery is inhibited by RuR and its derivative, Ru360 (68).
The major channel-forming subunit of the MCU complex
(CCDC109A) consists of two transmembrane and the N-terminal
domains and forms a complex in the IMM with many gatekeeper
membrane proteins (23, 24, 69–71). The calcium-sensing accessory subunits MICU1, MICU2, and MCUb are proposed to
serve as negative regulators, while mitochondrial Ca2+ uniporter
regulator 1 (MCUR1), essential MCU regulator, and SLC25A23
are essential for MCU activity (72–76). MCUR1 may, however,
also play other roles, such as in cytochrome c oxidase assembly
(77), as a cytosolic Ca2+-buffering agent (78), or in ROS generation (79).
The functional role of MCU under physiological conditions
was extensively studied using several silencing techniques
(80–85). Interestingly, MCU knockout mice did not exhibit
obvious defects in mitochondrial number or morphology and
any physiological function (82, 86, 87). MCU deletion was found
to be lethal for C57BL/6 mice, whereas knockout mice with
an outbred CD1 background were viable, albeit with reduced
numbers (88). Basal organ functions were maintained, and
impairment was only observed in the physiological adaptation
of skeletal muscle to exercise (82). In cardiac-specific conditional
MCU-deficient mice, the heart displayed increased resistance to
ischemia–reperfusion injury (87, 89).
VDAC1 Protein–Protein Interactions Regulate
[Ca2+]m Transport
Interactions between VDAC1 and Bcl-2 family proteins, such as
Bax/Bak, Bcl-2, and Bcl-xL, mediating the regulation of apoptosis,
are well documented (33, 47–55). It has been shown that interaction of Bcl-xL with VDAC1 or VDAC3 promoted [Ca2+]m uptake
(39). It was also reported that all three VDAC isoforms interact
with regulator of microtubule dynamics protein 3 (56), a protein
at the OMM involved in [Ca2+]i homeostasis regulation (57, 58).
VDAC1 interacts with endothelial NO synthase (eNOS), with
such interaction amplifying eNOS activity in a [Ca2+]i-mediated
manner (59). VDAC also interacts with the L-type Ca2+ channel,
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Na+/Ca2+ Exchanger Function in Ca2+
Efflux and Its Regulation
inhibited by RuR (111). Letm1 not only imports Ca2+ into the
matrix through the IMM but can also extrude Ca2+ from the
matrix when [Ca2+]m concentration is high (19, 109, 110).
Channels function in Ca2+ transport in membranes other
than in the mitochondria as ryanodine receptors (RyRs) and
the transient receptor potential 3 (TRPC3) channel were
reported to function in Ca2+ homeostasis [for review, see Ref.
(112, 113)]; RyRs, the main Ca2+-release channels in the SR/
ER in excitable cells, were reported to be expressed at the
IMM and mediate Ca2+ uptake in cardiomyocytes (114, 115).
Recently, it was demonstrated that neuronal mitochondria express
RyR at the IMM and accumulate Ca2+ in a manner that can be
inhibited by dantrolene or ryanodine (116). Finally, canonical
TRPC3 was shown to be located in the IMM and contributing to
[Ca2+]m uptake and thus functions in regulating [Ca2+]m homeostasis (117).
Mitochondrial Ca2+ is mainly determined by the balance
between influx through the MCU and efflux via NCLX (90). To
restore resting [Ca2+]m levels, Ca2+ efflux across IMM is mediated by the Na/Ca/Li exchanger (NCLX) or Na+/Ca2+ exchanger
(25, 26, 91), and possibly by Letm1, under certain conditions,
which functions as a Ca2+/H+ anti-porter in addition to being a
H+/K+ anti-porter (see Other Proteins Proposed as Participating
in or Mediating Ca2+ Efflux from Mitochondria) (92). NCLX
mediates efflux of Ca2+ from the mitochondrial matrix to the
IMS (20, 25, 93–95). In contrast to the plasma membrane
Na+/Ca2+ exchanger, NCLX transports Li+ ions in addition to
Na+ and Ca2+ (96). NCLX has also been proposed to regulate
Ca2+-induced NAD(P)H production and matrix redox state
modulation (97).
Mitochondrial Ca2+ regulates heart metabolism, where steadystate [Ca2+]m is determined by the dynamic balance between
MCU-based Ca2+ influx and NCLX-based Ca2+ efflux (98).
It has been proposed that a novel role of NCLX is to regulate
the automaticity of cardiomyocytes via modulating SR Ca2+
handling (99). NCLX has been proposed to be involved in
several pathological conditions. In ischemia, NCLX acts as a key
regulator of [Ca2+]m accumulation (100), while in diabetic cardiac
myocytes, NCLX is more susceptive to changes in the outside
(cytosolic) Na+ concentration, as compared with controls (101).
Phosphorylation of NCLX has been reported to reverse Ca2+
mitochondrial overload and promote survival of PINK1-deficient
dopaminergic neurons (102).
VDAC1 AT THE NEXUS OF
MITOCHONDRIA-MEDIATED APOPTOSIS
Mitochondria-mediated or intrinsic apoptotic pathway is activated via the release of mitochondrial pro-apoptotic proteins
(e.g., Cyto c, AIF, Smac/DIABLO) from the IMS to the cytosol
(32, 33, 52, 54, 118–126), leading to the activation of caspases.
Some models for the release of apoptotic proteins suggest that
release exclusively involves an increase in OMM permeability
due to the formation of a channel large enough to allow the
passage of apoptogenic proteins (32, 33, 124, 127–129), while
others consider release to be due to disruption of OMM integrity
(120, 130, 131). Recent studies demonstrated that upon apoptosis
induction, VDAC1 is oligomerized to form a large pore, allowing the release of mitochondrial pro-apoptotic proteins (129,
132–139). VDAC1 oligomerization was found to be a general
mechanism common to numerous apoptogens acting via different initiating cascades (135, 140, 141). Moreover, apoptosis
inhibitors (135, 142) and recently identified VDAC1-interacting
molecules [diphenylamine-2-carboxylate (DPC)] (40) and a
molecule developed in our lab designated as VBIT-4 were found
to prevent VDAC1 oligomerization and subsequent apoptosis
(143). Furthermore, cyathin-R, a cyathane-type diterpenoid
derived from a fungal secondary metabolite library from the
medicinal fungus Cyathus africanus, was found to interact with
purified VDAC1 and reduce its channel activity, as well as induce
apoptosis via promoting VDAC1 oligomerization and the associated cytochrome c release in Bax/Bak-depleted cells but not
when VDAC1 was depleted. Cyathin-R-induced apoptosis was
inhibited by DPC (142).
VDAC1 also regulates apoptosis via the direct interaction
with the anti-apoptotic protein HK (144–152), with apoptosisregulating proteins, such as Bcl-2, Bcl-xL (33, 47, 48, 50, 144,
153–155), and with the pro-apoptotic proteins Bax and Bak (156).
Other Proteins Proposed as Participating
in or Mediating Ca2+ Efflux from
Mitochondria
The transient opening of the mitochondrial permeability transition pore (MPTP or PTP) represents another mechanism for
Ca2+ release from mitochondria. However, its function is probably related to non-physiological Ca2+ overload that depolarizes
mitochondria by an irreversible opening of the PTP, leading
to apoptotic and necrotic cell death associated with disease
pathogenesis (103, 104). Multiple proteins have been proposed
to constitute the PTP and thus to play a role in PTP opening by
Ca2+ or ROS challenge, such as VDAC1 in the OMM, ANT in
the IMM, and cyclophilin D in the matrix (105, 106). However,
silencing approaches have only confirmed cyclophilin D as
being essential for Ca2+-sensitive PTP opening. One recent view
considered parts of the FoF1 ATPase as components of the PTP,
while other candidates has also emerged [for review, see Ref.
(107)]. Recently, SPG7 at the IMM has been proposed as a key
component of Ca2+- and ROS-induced PTP opening, forming
a complex with VDAC1 at the OMM and cyclophilin D in the
matrix (108).
A potential candidate for the [Ca2+]m/H+ anti-porter was suggested, the leucine zipper-EF-hand-containing transmembrane
protein 1 (Letm1) (19, 92, 109–111). Letm1 has two Ca2+-binding
EF hand domains and catalyzes the electronic exchange of Ca2+
for H+. Letm1 Ca2+ transport activity is pH-sensitive and is
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Ca2+-Induced Apoptosis through VDAC1
Overexpression
Apoptosis induction affects cell Ca2+ homeostasis and energy
production (157). The intrinsic apoptotic pathway, initiated
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in response to various stimuli, including high [Ca2+]i, oxygen
radicals, activation of pro-apoptotic Bcl-2 family proteins, UV
damage, and various anticancer drugs and cytotoxic agents, such
as thapsigargin, staurosporine, As2O3, and selenite, disrupts cellular Ca2+ homeostasis and induces apoptosis (140). Indeed, the
contribution of Ca2+ signals to cell death is well documented, and
a few mechanisms that connect apoptotic stimuli, via a rise in
[Ca2+]i, to cell death have been suggested (158–164).
Recently, it was demonstrated that a panel of apoptotic
inducers, such as UV irradiation, H2O2, etoposide, cisplatin, or
selenite, elevated [Ca2+]i and upregulated VDAC1 expression
levels in a Ca2+-dependent manner (Table 1), resulting in VDAC1
oligomerization, Cyto c release, and subsequent apoptosis (140,
141) (Figure 2). Furthermore, direct elevation of [Ca2+]i by the
Ca2+-mobilizing agents A23187, ionomycin, or thapsigargin led to
VDAC1 overexpression, VDAC1 oligomerization, and apoptosis,
while decreasing [Ca2+]i using the cell-permeable Ca2+-chelating
reagent BAPTA-AM inhibited these events (141).
It has also been shown that the sensitivity of the CD45-positive
(CD45+) U266 myeloma cell line to various apoptotic stimuli is
well correlated with the elevated levels of VDAC1 expression
that follow Ca2+ signals in response to apoptosis stimulation
(169, 175). This suggests that apoptosis-inducing agents act by
increasing [Ca2+]i and that this, in turn, leads to an upregulation
of VDAC1 expression, which is connected to apoptosis induction
(Table 1). The proposed sequence of events leading to VDAC1mediated apoptosis can be schematically depicted as:
Support for this model comes with the findings that several
VDAC-interacting molecules prevent its oligomerization, the
elevation in [Ca2+]i associated with apoptosis induction, Cyto c
release, and apoptosis (40, 41, 141, 151, 165, 166, 170, 171, 173,
176–178). DIDS was shown to prevent the apoptosis stimuliinducing increase in [Ca2+]i levels (40) and Ca2+-mediated oxidative stress and apoptosis, as induced by 5-aminolevulinic (41).
The small molecules AKOS-022 and VBIT-4 that bind to VDAC1
prevent its oligomerization, the elevation [Ca2+]i associated
with apoptosis induction, Cyto c release, and apoptosis (166).
Furthermore, mitochondria-mediated apoptosis was correlated
with VDAC1 expression levels (141, 165–175). Thus, although
different apoptosis inducers elicit cell death via different mechanisms, all induce VDAC1 overexpression in a Ca2+-dependent
manner, raising the possibility that elevating [Ca2+]i represents a
common mechanism for various apoptosis stimuli, subsequently
leading to an elevation in VDAC1 expression. We, therefore,
suggest that the upregulation of VDAC1 expression constitutes a
major mechanism by which apoptosis inducers lead to apoptosis
(Figure 2).
TABLE 1 | Anticancer, pro-apoptotic drugs, and chemical agents that increase voltage-dependent anion channel 1 expression level in cancer cells.
Drugs or chemical agent
Cancer cell type
Reference
Prednisolone—synthetic glucocorticoid, a derivative of cortisol, used to
treat a variety of inflammatory and autoimmune conditions and some
cancers
Acute lymphoblastic leukemia cell lines, REH, 697, Sup-B15, and
RS4;11
Cisplatin—a chemotherapy drug, the first member of a class of platinumcontaining anticancer drugs
Cervix squamous cell carcinoma line (A431), human cervical
adenocarcinoma (HeLa), non-small human lung carcinoma (A549), and
human ovarian carcinoma (SKOV3)
Mechlorethamine and its derivative, melphalan—DNA cross-linking agents, Human cervical adenocarcinoma (HeLa)
a group of anticancer chemotherapeutic drugs
(165)
(141, 166)
(167)
ROS—reactive oxygen species (H2O2 and sodium nitroprusside)
Human cervical adenocarcinoma (HeLa), non-small human lung
carcinoma (A549), human ovarian carcinoma (SKOV3), and rat PC12
cells
UV irradiation
B cell mouse lymphoma (LYas)
Arbutin—(hydroquinone-O-β-D-glucopyranoside), tyrosinase inhibitor, and
potential anticancer agent, extracted from the bearberry plant
Human malignant melanoma cells (A375)
Orf3—hepatitis E virus protein
Hepatoma cells
(172)
Somatostatin—a peptide hormone
Human prostate cancer cell line (LNCaP)
(173)
Endostatin—20-kDa C-terminal fragment derived from type XVIII collage
Human microvascular endothelial cells
(126)
Selenite—inorganic compound
Human cervix carcinoma (HeLa) cells
(141, 174)
Thapsigargin—non-competitive inhibitor of the sarco/endoplasmic
reticulum Ca2+-ATPase, extracted from the plant Thapsia garganica
U266 myeloma cells and human cervical adenocarcinoma (HeLa) cells
(141, 175)
Etoposide—topoisomerase inhibitor, cytotoxic anticancer drug
Human cervical adenocarcinoma (HeLa), non-small human lung
carcinoma (A549), and human ovarian carcinoma (SKOV3)
(141)
Arsenic trioxide ( As2 O3− )—inorganic compound
Human cervical adenocarcinoma (HeLa), non-small human lung
carcinoma (A549), and human ovarian carcinoma (SKOV3)
(141)
Frontiers in Oncology | www.frontiersin.org
6
(141, 168)
(169)
(170, 171)
April 2017 | Volume 7 | Article 60
Shoshan-Barmatz et al.
VDAC1 in Ca2+ Signaling and Apoptosis
FIGURE 2 | Proposed model for apoptosis stimuli-induced increase in voltage-dependent anion channel 1 (VDAC1) expression levels leading to
VDAC1 oligomerization, Cyto c release, and apoptosis and possible inhibition steps. A schematic model describing the novel pathway proposed for
apoptosis induction involving elevation of [Ca2+]i leading to VDAC1 overexpression. (A) This facilitates VDAC1 oligomerization to form a large channel mediating
cytochrome c release from the mitochondrion into the cytosol, resulting in apoptosis activation. It is proposed that the overexpression of VDAC1 in diseases such as
Alzheimer’s disease, cardiovascular diseases, and diabetes is associated mitochondrial dysfunction, including apoptosis induction (B).
Although many studies in various experimental systems have
demonstrated increased VDAC1 expression levels following
apoptosis stimulation (Table 1), only a few have linked VDAC1
overexpression to the rise in [Ca2+]i following apoptosis induction. Indeed, the expression level of VDAC1 has been shown
to be a crucial factor in the process of mitochondria-mediated
apoptosis (141, 165–175). Moreover, exogenous VDAC1 expression leads to apoptosis in the absence of any apoptotic stimulus
(32, 34, 137, 141, 144, 151, 165, 179). There are several potential
Ca2+-dependent steps that could contribute to the process of gene
expression and a few, such as mRNA transcription, elongation,
splicing, stability, and translation, have been suggested as being
regulated by Ca2+ (180, 181).
This new mode of action for apoptosis stimulus involving
increased expression of VDAC1 leading to dynamic VDAC1
oligomerization, release of Cyto c, and apoptosis provides a platform for developing a new class of anticancer drugs modulating
VDAC1 expression via its promoter.
participates in processes that determine Ca2+ dynamics and
homeostasis, as well as changes in sensitivity to cell death induction (186). It was recently demonstrated that the basal [Ca2+]m
uptake via the ER–mitochondria junction is essential for tumorigenic cell viability, and that inhibition of this pathway in cancer
cells might be used as a therapeutic approach (187). Moreover,
some cancer cells are addicted to such constitutive Ca2+ transfer to
sustain their mitochondrial metabolism, particularly nucleoside
production (188). Thus, the increase in VDAC1 levels in cancer
(182, 183) also contributes to this enhanced transport of Ca2+.
In diabetic mouse coronary vascular endothelial cells (MCECs),
VDAC levels were increased, as were [Ca2+]m, mitochondrial O2
production, and PTP opening activity (189). Downregulation of
VDAC1 in diabetic MCECs decreased [Ca2+]m and subsequently
normalized the levels of PTP activity and mitochondrial ROS
production (190). VDAC1 has proposed to mediate the protective
effects of hesperidin, a bioactive flavonoid compound, against
amyloid β-induced mitochondrial dysfunction, mitochondrial
PTP opening, [Ca2+]i increase, and ROS production (191). It has
also shown that blocking of VDAC1-mediated [Ca2+]m release
in Schwann cells prevented demyelinating neuropathies (192).
Thus, VDAC function in Ca2+ homeostasis is connected to several
diseases.
VDAC1 AND Ca2+ IN CANCER AND OTHER
DISEASES
Various cancer hallmarks, such as proliferation, migration,
angiogenesis, invasion abilities, and resistance to cell death,
are associated with alterations of Ca2+ homeostasis (2). As a
transporter of metabolites and Ca2+, VDAC1 contributes to the
metabolic phenotype of cancer cells, possibly as reflected in
its overexpression in many cancer types (182, 183). Moreover,
its downregulation resulted in reduced metabolite exchanges
between mitochondria and cytosol and inhibited cell and tumor
growth (122, 176, 182, 184, 185).
Tumor cells exhibit a well-developed capacity for modulating [Ca2+]i levels by remodeling the cellular machinery that
Frontiers in Oncology | www.frontiersin.org
AUTHOR CONTRIBUTIONS
VS-B wrote the review; SD and AM helped in writing.
FUNDING
This research was supported by a grant from the Israel Science
Foundation 307/13 and by Sima and Philip Needleman research
funds.
7
April 2017 | Volume 7 | Article 60
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VDAC1 in Ca2+ Signaling and Apoptosis
REFERENCES
24. De Stefani D, Raffaello A, Teardo E, Szabo I, Rizzuto R. A forty-kilodalton
protein of the inner membrane is the mitochondrial calcium uniporter.
Nature (2011) 476:336–40. doi:10.1038/nature10230
25. Palty R, Silverman WF, Hershfinkel M, Caporale T, Sensi SL, Parnis
J, et al. NCLX is an essential component of mitochondrial Na+/Ca2+
exchange. Proc Natl Acad Sci U S A (2010) 107:436–41. doi:10.1073/
pnas.0908099107
26. Boyman L, Williams GS, Khananshvili D, Sekler I, Lederer WJ. NCLX:
the mitochondrial sodium calcium exchanger. J Mol Cell Cardiol (2013)
59:205–13. doi:10.1016/j.yjmcc.2013.03.012
27. Gincel D, Zaid H, Shoshan-Barmatz V. Calcium binding and translocation
by the voltage-dependent anion channel: a possible regulatory mechanism
in mitochondrial function. Biochem J (2001) 358:147–55. doi:10.1042/
bj3580147
28. Rapizzi E, Pinton P, Szabadkai G, Wieckowski MR, Vandecasteele G, Baird
G, et al. Recombinant expression of the voltage-dependent anion channel
enhances the transfer of Ca2+ microdomains to mitochondria. J Cell Biol
(2002) 159:613–24. doi:10.1083/jcb.200205091
29. Tan W, Colombini M. VDAC closure increases calcium ion flux. Biochim
Biophys Acta (2007) 1768:2510–5. doi:10.1016/j.bbamem.2007.06.002
30. Bathori G, Csordas G, Garcia-Perez C, Davies E, Hajnoczky G.
Ca2+-dependent control of the permeability properties of the mitochondrial outer membrane and voltage-dependent anion-selective
channel (VDAC). J Biol Chem (2006) 281:17347–58. doi:10.1074/jbc.
M600906200
31. De Pinto V, Guarino F, Guarnera A, Messina A, Reina S, Tomasello FM, et al.
Characterization of human VDAC isoforms: a peculiar function for VDAC3?
Biochim Biophys Acta (2010) 1797:1268–75. doi:10.1016/j.bbabio.2010.01.031
32. Shoshan-Barmatz V, Ben-Hail D. VDAC, a multi-functional mitochondrial
protein as a pharmacological target. Mitochondrion (2012) 12:24–34.
doi:10.1016/j.mito.2011.04.001
33. Shoshan-Barmatz V, De Pinto V, Zweckstetter M, Raviv Z, Keinan N, Arbel
N. VDAC, a multi-functional mitochondrial protein regulating cell life and
death. Mol Aspects Med (2010) 31:227–85. doi:10.1016/j.mam.2010.03.002
34. Shoshan-Barmatz V, Mizrachi D. VDAC1: from structure to cancer therapy.
Front Oncol (2012) 2:164. doi:10.3389/fonc.2012.00164
35. Dolder M, Wendt S, Wallimann T. Mitochondrial creatine kinase in contact
sites: interaction with porin and adenine nucleotide translocase, role in permeability transition and sensitivity to oxidative damage. Biol Signals Recept
(2001) 10:93–111. doi:10.1159/000046878
36. Wu W, Zhao S. Metabolic changes in cancer: beyond the Warburg effect. Acta
Biochim Biophys Sin (Shanghai) (2013) 45:18–26. doi:10.1093/abbs/gms104
37. Madesh M, Hajnoczky G. VDAC-dependent permeabilization of the outer
mitochondrial membrane by superoxide induces rapid and massive cytochrome c release. J Cell Biol (2001) 155:1003–15. doi:10.1083/jcb.200105057
38. De Stefani D, Bononi A, Romagnoli A, Messina A, De Pinto V, Pinton P, et al.
VDAC1 selectively transfers apoptotic Ca2+ signals to mitochondria. Cell
Death Differ (2012) 19:267–73. doi:10.1038/cdd.2011.92
39. Huang H, Hu X, Eno CO, Zhao G, Li C, White C. An interaction between
Bcl-xL and the voltage-dependent anion channel (VDAC) promotes mitochondrial Ca2+ uptake. J Biol Chem (2013) 288:19870–81. doi:10.1074/jbc.
M112.448290
40. Ben-Hail D, Shoshan-Barmatz V. VDAC1-interacting anion transport inhibitors inhibit VDAC1 oligomerization and apoptosis. Biochim Biophys Acta
(2016) 1863:1612–23. doi:10.1016/j.bbamcr.2016.04.002
41. Chen H, Gao W, Yang Y, Guo S, Wang H, Wang W, et al. Inhibition of
VDAC1 prevents Ca(2)(+)-mediated oxidative stress and apoptosis induced
by 5-aminolevulinic acid mediated sonodynamic therapy in THP-1 macrophages. Apoptosis (2014) 19:1712–26. doi:10.1007/s10495-014-1045-5
42. Charuk JH, Pirraglia CA, Reithmeier RA. Interaction of ruthenium
red with Ca2(+)-binding proteins. Anal Biochem (1990) 188:123–31.
doi:10.1016/0003-2697(90)90539-L
43. Israelson A, Abu-Hamad S, Zaid H, Nahon E, Shoshan-Barmatz V.
Localization of the voltage-dependent anion channel-1 Ca2+-binding sites.
Cell Calcium (2007) 41:235–44. doi:10.1016/j.ceca.2006.06.005
44. Gincel D, Vardi N, Shoshan-Barmatz V. Retinal voltage-dependent anion
channel: characterization and cellular localization. Invest Ophthalmol Vis Sci
(2002) 43:2097–104.
1. Berridge MJ, Bootman MD, Roderick HL. Calcium signalling: dynamics,
homeostasis and remodelling. Nat Rev Mol Cell Biol (2003) 4:517–29.
doi:10.1038/nrm1155
2. Roderick HL, Cook SJ. Ca2+ signalling checkpoints in cancer: remodelling
Ca2+ for cancer cell proliferation and survival. Nat Rev Cancer (2008)
8:361–75. doi:10.1038/nrc2374
3. Berridge MJ, Lipp P, Bootman MD. The versatility and universality of calcium signalling. Nat Rev Mol Cell Biol (2000) 1:11–21.
doi:10.1038/35036191
4. Rizzuto R, De Stefani D, Raffaello A, Mammucari C. Mitochondria as sensors
and regulators of calcium signalling. Nat Rev Mol Cell Biol (2012) 13:566–78.
doi:10.1038/nrm3412
5. Cox DA, Matlib MA. A role for the mitochondrial Na(+)-Ca2+ exchanger in
the regulation of oxidative phosphorylation in isolated heart mitochondria.
J Biol Chem (1993) 268:938–47.
6. Glancy B, Balaban RS. Role of mitochondrial Ca2+ in the regulation
of cellular energetics. Biochemistry (2012) 51:2959–73. doi:10.1021/
bi2018909
7. Nicholls DG. Mitochondria and calcium signaling. Cell Calcium (2005)
38:311–7. doi:10.1016/j.ceca.2005.06.011
8. Gunter TE, Buntinas L, Sparagna G, Eliseev R, Gunter K. Mitochondrial calcium transport: mechanisms and functions. Cell Calcium (2000) 28:285–96.
doi:10.1054/ceca.2000.0168
9. Xia H, Mao Q, Eliason SL, Harper SQ, Martins IH, Orr HT, et al. RNAi
suppresses polyglutamine-induced neurodegeneration in a model of spinocerebellar ataxia. Nat Med (2004) 10:816–20. doi:10.1038/nm1076
10. Giacomello M, Drago I, Pizzo P, Pozzan T. Mitochondrial Ca2+ as a key regulator of cell life and death. Cell Death Differ (2007) 14:1267–74. doi:10.1038/
sj.cdd.4402147
11. Maechler P, Kennedy ED, Pozzan T, Wollheim CB. Mitochondrial activation
directly triggers the exocytosis of insulin in permeabilized pancreatic betacells. EMBO J (1997) 16:3833–41. doi:10.1093/emboj/16.13.3833
12. Lee B, Miles PD, Vargas L, Luan P, Glasco S, Kushnareva Y, et al. Inhibition
of mitochondrial Na+-Ca2+ exchanger increases mitochondrial metabolism
and potentiates glucose-stimulated insulin secretion in rat pancreatic islets.
Diabetes (2003) 52:965–73. doi:10.2337/diabetes.52.4.965
13. Prins D, Michalak M. Organellar calcium buffers. Cold Spring Harb Perspect
Biol (2011) 3:1–16. doi:10.1101/cshperspect.a004069
14. Denton RM. Regulation of mitochondrial dehydrogenases by calcium ions.
Biochim Biophys Acta (2009) 1787:1309–16. doi:10.1016/j.bbabio.2009.01.005
15. Nichols BJ, Denton RM. Towards the molecular basis for the regulation of
mitochondrial dehydrogenases by calcium ions. Mol Cell Biochem (1995)
149:203–12. doi:10.1007/BF01076578
16. Cardenas C, Miller RA, Smith I, Bui T, Molgo J, Muller M, et al. Essential
regulation of cell bioenergetics by constitutive InsP3 receptor Ca2+ transfer
to mitochondria. Cell (2010) 142:270–83. doi:10.1016/j.cell.2010.06.007
17. Rizzuto R, Bernardi P, Pozzan T. Mitochondria as all-round players of the calcium game. J Physiol (2000) 529:37–47. doi:10.1111/j.1469-7793.2000.00037.x
18. De Stefani D, Rizzuto R, Pozzan T. Enjoy the trip: calcium in mitochondria back and forth. Annu Rev Biochem (2016) 85:161–92. doi:10.1146/
annurev-biochem-060614-034216
19. Santo-Domingo J, Demaurex N. Calcium uptake mechanisms of mitochondria. Biochim Biophys Acta (2010) 1797:907–12. doi:10.1016/j.
bbabio.2010.01.005
20. Sekler I. Standing of giants shoulders the story of the mitochondrial Na+Ca2+
exchanger. Biochem Biophys Res Commun (2015) 460:50–2. doi:10.1016/j.
bbrc.2015.02.170
21. Takeuchi A, Kim B, Matsuoka S. The destiny of Ca(2+) released by mitochondria. J Physiol Sci (2015) 65:11–24. doi:10.1007/s12576-014-0326-7
22. Nita LI, Hershfinkel M, Sekler I. Life after the birth of the mitochondrial Na+/
Ca2+ exchanger, NCLX. Sci China Life Sci (2015) 58:59–65. doi:10.1007/
s11427-014-4789-9
23. Baughman JM, Perocchi F, Girgis HS, Plovanich M, Belcher-Timme CA,
Sancak Y, et al. Integrative genomics identifies MCU as an essential component of the mitochondrial calcium uniporter. Nature (2011) 476:341–5.
doi:10.1038/nature10234
Frontiers in Oncology | www.frontiersin.org
8
April 2017 | Volume 7 | Article 60
Shoshan-Barmatz et al.
VDAC1 in Ca2+ Signaling and Apoptosis
45. Israelson A, Arzoine L, Abu-hamad S, Khodorkovsky V, Shoshan-Barmatz
V. A photoactivable probe for calcium binding proteins. Chem Biol (2005)
12:1169–78. doi:10.1016/j.chembiol.2005.08.006
46. Israelson A, Zaid H, Abu-Hamad S, Nahon E, Shoshan-Barmatz V.
Mapping the ruthenium red-binding site of the voltage-dependent
anion channel-1. Cell Calcium (2008) 43:196–204. doi:10.1016/j.
ceca.2007.05.006
47. Arbel N, Ben-Hail D, Shoshan-Barmatz V. Mediation of the antiapoptotic
activity of Bcl-xL protein upon interaction with VDAC1 protein. J Biol Chem
(2012) 287:23152–61. doi:10.1074/jbc.M112.345918
48. Arbel N, Shoshan-Barmatz V. Voltage-dependent anion channel 1-based
peptides interact with Bcl-2 to prevent antiapoptotic activity. J Biol Chem
(2010) 285:6053–62. doi:10.1074/jbc.M109.082990
49. Kholmukhamedov EL, Czerny C, Lovelace G, Beeson KC, Baker T, Johnson
CB, et al. [The role of the voltage-dependent anion channels in the outer
membrane of mitochondria in the regulation of cellular metabolism].
Biofizika (2010) 55:822–33.
50. Malia TJ, Wagner G. NMR structural investigation of the mitochondrial
outer membrane protein VDAC and its interaction with antiapoptotic
Bcl-xL. Biochemistry (2007) 46:514–25. doi:10.1021/bi061577h
51. Monaco G, Decrock E, Arbel N, van Vliet AR, La Rovere RM, De Smedt H,
et al. The BH4 domain of anti-apoptotic Bcl-XL, but not that of the related
Bcl-2, limits the voltage-dependent anion channel 1 (VDAC1)-mediated
transfer of pro-apoptotic Ca2+ signals to mitochondria. J Biol Chem (2015)
290:9150–61. doi:10.1074/jbc.M114.622514
52. Shimizu S, Konishi A, Kodama T, Tsujimoto Y. BH4 domain of antiapoptotic
Bcl-2 family members closes voltage-dependent anion channel and inhibits
apoptotic mitochondrial changes and cell death. Proc Natl Acad Sci U S A
(2000) 97:3100–5. doi:10.1073/pnas.97.7.3100
53. Sugiyama T, Shimizu S, Matsuoka Y, Yoneda Y, Tsujimoto Y. Activation
of mitochondrial voltage-dependent anion channel by a pro-apoptotic
BH3-only protein Bim. Oncogene (2002) 21:4944–56. doi:10.1038/
sj.onc.1205621
54. Tajeddine N, Galluzzi L, Kepp O, Hangen E, Morselli E, Senovilla L, et al.
Hierarchical involvement of Bak, VDAC1 and Bax in cisplatin-induced cell
death. Oncogene (2008) 27:4221–32. doi:10.1038/onc.2008.63
55. Tsujimoto Y. Cell death regulation by the Bcl-2 protein family in the mitochondria. J Cell Physiol (2003) 195:158–67. doi:10.1002/jcp.10254
56. Hein MY, Hubner NC, Poser I, Cox J, Nagaraj N, Toyoda Y, et al. A human
interactome in three quantitative dimensions organized by stoichiometries
and abundances. Cell (2015) 163:712–23. doi:10.1016/j.cell.2015.09.053
57. Lv BF, Yu CF, Chen YY, Lu Y, Guo JH, Song QS, et al. Protein tyrosine phosphatase interacting protein 51 (PTPIP51) is a novel mitochondria protein
with an N-terminal mitochondrial targeting sequence and induces apoptosis.
Apoptosis (2006) 11:1489–501. doi:10.1007/s10495-006-8882-9
58. De Vos KJ, Mórotz GM, Stoica R, Tudor EL, Lau K-F, Ackerley S, et al.
VAPB interacts with the mitochondrial protein PTPIP51 to regulate calcium
homeostasis. Hum Mol Genet (2012) 21:1299–311. doi:10.1093/hmg/ddr559
59. Sun J, Liao JK. Functional interaction of endothelial nitric oxide synthase
with a voltage-dependent anion channel. Proc Natl Acad Sci U S A (2002)
99:13108–13. doi:10.1073/pnas.202260999
60. Viola HM, Adams AM, Davies SM, Fletcher S, Filipovska A, Hool LC.
Impaired functional communication between the L-type calcium channel
and mitochondria contributes to metabolic inhibition in the mdx heart. Proc
Natl Acad Sci U S A (2014) 111:E2905–14. doi:10.1073/pnas.1402544111
61. Shoshan-Barmatz V, Israelson A. The voltage-dependent anion channel
in endoplasmic/sarcoplasmic reticulum: characterization, modulation
and possible function. J Membr Biol (2005) 204:57–66. doi:10.1007/
s00232-005-0749-4
62. Shoshan-Barmatz V, Zalk R, Gincel D, Vardi N. Subcellular localization of
VDAC in mitochondria and ER in the cerebellum. Biochim Biophys Acta
(2004) 1657:105–14. doi:10.1016/j.bbabio.2004.02.009
63. Csordás G, Renken C, Várnai P, Walter L, Weaver D, Buttle KF, et al. Structural
and functional features and significance of the physical linkage between ER
and mitochondria. J Cell Biol (2006) 174:915–21. doi:10.1083/jcb.200604016
64. Marchi S, Patergnani S, Pinton P. The endoplasmic reticulum-mitochondria
connection: one touch, multiple functions. Biochim Biophys Acta (2014)
1837:461–9. doi:10.1016/j.bbabio.2013.10.015
Frontiers in Oncology | www.frontiersin.org
65. Booth DM, Joseph SK, Hajnoczky G. Subcellular ROS imaging methods:
relevance for the study of calcium signaling. Cell Calcium (2016) 60:65–73.
doi:10.1016/j.ceca.2016.05.001
66. Bernardi P. Mitochondrial transport of cations: channels, exchangers, and
permeability transition. Physiol Rev (1999) 79:1127–55.
67. Foskett JK, Philipson B. The mitochondrial Ca2 + uniporter complex. J Mol
Cell Cardiol (2015) 78:3–8. doi:10.1016/j.yjmcc.2014.11.015
68. Vasington FD, Gazzotti P, Tiozzo R, Carafoli E. The effect of ruthenium
red on Ca 2+ transport and respiration in rat liver mitochondria. Biochim
Biophys Acta (1972) 256:43–54. doi:10.1016/0005-2728(72)90161-2
69. Kamer KJ, Sancak Y, Mootha VK. The uniporter: from newly identified parts
to function. Biochem Biophys Res Commun (2014) 449:370–2. doi:10.1016/j.
bbrc.2014.04.143
70. Marchi S, Pinton P. The mitochondrial calcium uniporter complex: molecular
components, structure and physiopathological implications. J Physiol (2014)
592:829–39. doi:10.1113/jphysiol.2013.268235
71. Lee Y, Min CK, Kim TG, Song HK, Lim Y, Kim D, et al. Structure and function
of the N-terminal domain of the human mitochondrial calcium uniporter.
EMBO Rep (2015) 16:1318–33. doi:10.15252/embr.201540436
72. Csordás G, Golenár T, Seifert EL, Kamer KJ, Sancak Y, Perocchi F, et al.
MICU1 controls both the threshold and cooperative activation of the mitochondrial Ca(2+) uniporter. Cell Metab (2013) 17:976–87. doi:10.1016/j.
cmet.2013.04.020
73. Hoffman NE, Chandramoorthy HC, Shanmughapriya S, Zhang XQ, Vallem
S, Doonan PJ, et al. SLC25A23 augments mitochondrial Ca2+ uptake, interacts with MCU, and induces oxidative stress-mediated cell death. Mol Biol
Cell (2014) 25:936–47. doi:10.1091/mbc.E13-08-0502
74. Mallilankaraman K, Doonan P, Cárdenas C, Chandramoorthy HC, Müller
M, Miller R, et al. MICU1 is an essential gatekeeper for MCU-mediated mitochondrial Ca2+ uptake that regulates cell survival. Cell (2012) 151:630–44.
doi:10.1016/j.cell.2012.10.011
75. Plovanich M, Bogorad RL, Sancak Y, Kamer KJ, Strittmatter L, Li AA,
et al. MICU2, a paralog of MICU1, resides within the mitochondrial uniporter complex to regulate calcium handling. PLoS One (2013) 8:e55785.
doi:10.1371/journal.pone.0055785
76. Sancak Y, Markhard AL, Kitami T, Kovács-Bogdán E, Kamer KJ, Udeshi ND,
et al. EMRE is an essential component of the mitochondrial calcium uniporter complex. Science (2013) 342:1379–82. doi:10.1126/science.1242993
77. Paupe V, Prudent J, Dassa EP, Rendon OZ, Shoubridge EA. CCDC90A
(MCUR1) is a cytochrome c oxidase assembly factor and not a regulator
of the mitochondrial calcium uniporter. Cell Metab (2015) 21:109–16.
doi:10.1016/j.cmet.2014.12.004
78. Pozzan T, Magalhaes P, Rizzuto R. The comeback of mitochondria to calcium
signalling. Cell Calcium (2000) 28:279–83. doi:10.1054/ceca.2000.0166
79. Xu S, Chisholm AD. C. elegans epidermal wounding induces a mitochondrial ROS burst that promotes wound repair. Dev Cell (2014) 31:48–60.
doi:10.1016/j.devcel.2014.08.002
80. Alam MR, Groschner LN, Parichatikanond W, Kuo L, Bondarenko AI,
Rost R, et al. Mitochondrial Ca2+ uptake 1 (MICU1) and mitochondrial
Ca2+ uniporter (MCU) contribute to metabolism-secretion coupling in
clonal pancreatic β-cells. J Biol Chem (2012) 287:34445–54. doi:10.1074/jbc.
M112.392084
81. Drago I, De Stefani D, Rizzuto R, Pozzan T. Mitochondrial Ca2+ uptake
contributes to buffering cytoplasmic Ca2+ peaks in cardiomyocytes. Proc
Natl Acad Sci U S A (2012) 109:12986–91. doi:10.1073/pnas.1210718109
82. Pan X, Liu J, Nguyen T, Liu C, Sun J, Teng Y, et al. The physiological role of
mitochondrial calcium revealed by mice lacking the mitochondrial calcium
uniporter. Nat Cell Biol (2013) 15:1464–72. doi:10.1038/ncb2868
83. Qiu J, Tan Y-W, Hagenston AM, Martel M-A, Kneisel N, Skehel PA, et al.
Mitochondrial calcium uniporter MCU controls excitotoxicity and is
transcriptionally repressed by neuroprotective nuclear calcium signals. Nat
Commun (2013) 4:2034. doi:10.1038/ncomms3034
84. Quan X, Nguyen TT, Choi S-K, Xu S, Das R, Cha S-K, et al. Essential role
of mitochondrial Ca2+ uniporter in the generation of mitochondrial pH
gradient and metabolism-secretion coupling in insulin-releasing cells. J Biol
Chem (2015) 290:4086–96. doi:10.1074/jbc.M114.632547
85. Rasmussen TP, Wu Y, Joiner ML, Koval OM, Wilson NR, Luczak ED,
et al. Inhibition of MCU forces extramitochondrial adaptations governing
9
April 2017 | Volume 7 | Article 60
Shoshan-Barmatz et al.
86.
87.
88.
89.
90.
91.
92.
93.
94.
95.
96.
97.
98.
99.
100.
101.
102.
103.
104.
105.
VDAC1 in Ca2+ Signaling and Apoptosis
physiological and pathological stress responses in heart. Proc Natl Acad Sci
U S A (2015) 112:9129–34. doi:10.1073/pnas.1504705112
Holmström KM, Pan X, Liu JC, Menazza S, Liu J, Nguyen TT, et al. Assessment
of cardiac function in mice lacking the mitochondrial calcium uniporter.
J Mol Cell Cardiol (2015) 85:178–82. doi:10.1016/j.yjmcc.2015.05.022
Luongo TS, Lambert JP, Yuan A, Zhang X, Gross P, Song J, et al. The mitochondrial calcium uniporter matches energetic supply with cardiac workload during stress and modulates permeability transition. Cell Rep (2015)
12:23–34. doi:10.1016/j.celrep.2015.06.017
Murphy E, Pan X, Nguyen T, Liu J, Holmstrom KM, Finkel T. Unresolved
questions from the analysis of mice lacking MCU expression. Biochem
Biophys Res Commun (2014) 449:384–5. doi:10.1016/j.bbrc.2014.04.144
Kwong JQ, Lu X, Correll RN, Schwanekamp JA, Vagnozzi RJ, Sargent MA,
et al. The mitochondrial calcium uniporter selectively matches metabolic
output to acute contractile stress in the heart. Cell Rep (2015) 12:15–22.
doi:10.1016/j.celrep.2015.06.002
Murphy E, Eisner DA. Regulation of intracellular and mitochondrial
Na in health and disease. Circ Res (2009) 104:292–303. doi:10.1161/
CIRCRESAHA.108.189050
Kim B, Takeuchi A, Hikida M, Matsuoka S. Roles of the mitochondrial
Na(+)-Ca(2+) exchanger, NCLX, in B lymphocyte chemotaxis. Sci Rep
(2016) 6:28378. doi:10.1038/srep28378
Jiang D, Zhao L, Clish CB, Clapham DE. Letm1, the mitochondrial Ca2+/
H+ antiporter, is essential for normal glucose metabolism and alters brain
function in Wolf-Hirschhorn syndrome. Proc Natl Acad Sci U S A (2013)
110:E2249–54. doi:10.1073/pnas.1308558110
Palty R, Hershfinkel M, Sekler I. Molecular identity and functional properties
of the mitochondrial Na+/Ca2+ exchanger. J Biol Chem (2012) 287:31650–7.
doi:10.1074/jbc.R112.355867
Arco AD, Satrústegui J. New mitochondrial carriers: an overview. Cell Mol
Life Sci (2005) 62:2204–27. doi:10.1007/s00018-005-5197-x
McCormack JG, Denton RM. Mitochondrial Ca2+ transport and the role
of intramitochondrial Ca2+ in the regulation of energy metabolism. Dev
Neurosci (1993) 15:165–73. doi:10.1159/000111332
Palty R, Ohana E, Hershfinkel M, Volokita M, Elgazar V, Beharier O, et al.
Lithium-calcium exchange is mediated by a distinct potassium-independent
sodium-calcium exchanger. J Biol Chem (2004) 279:25234–40. doi:10.1074/
jbc.M401229200
De Marchi U, Santo-Domingo J, Castelbou C, Sekler I, Wiederkehr A,
Demaurex N. NCLX protein, but not LETM1, mediates mitochondrial Ca2+
extrusion, thereby limiting Ca2+-induced NAD(P)H production and modulating matrix redox state. J Biol Chem (2014) 289:20377–85. doi:10.1074/
jbc.M113.540898
Williams GS, Boyman L, Lederer WJ. Mitochondrial calcium and the
regulation of metabolism in the heart. J Mol Cell Cardiol (2015) 78:35–45.
doi:10.1016/j.yjmcc.2014.10.019
Takeuchi A, Kim B, Matsuoka S. The mitochondrial Na+-Ca2+ exchanger,
NCLX, regulates automaticity of HL-1 cardiomyocytes. Sci Rep (2013)
3:2766. doi:10.1038/srep02766
Murphy E, Cross H, Steenbergen C. Sodium regulation during ischemia
versus reperfusion and its role in injury. Circ Res (1999) 84:1469–70.
doi:10.1161/01.RES.84.12.1469
Babsky A, Doliba N, Doliba N, Savchenko A, Wehrli S, Osbakken M. Na+
effects on mitochondrial respiration and oxidative phosphorylation in
diabetic hearts. Exp Biol Med (2001) 226:543–51.
Kostic M, Ludtmann MH, Bading H, Hershfinkel M, Steer E, Chu CT, et al.
PKA phosphorylation of NCLX reverses mitochondrial calcium overload
and depolarization, promoting survival of PINK1-deficient dopaminergic
neurons. Cell Rep (2015) 13:376–86. doi:10.1016/j.celrep.2015.08.079
Tsujimoto Y, Shimizu S. Role of the mitochondrial membrane permeability transition in cell death. Apoptosis (2007) 12:835–40. doi:10.1007/
s10495-006-0525-7
Rasola A, Bernardi P. Mitochondrial permeability transition in Ca2+dependent apoptosis and necrosis. Cell Calcium (2011) 50:222–33.
doi:10.1016/j.ceca.2011.04.007
Elrod JW, Wong R, Mishra S, Vagnozzi RJ, Sakthievel B, Goonasekera
SA, et al. Cyclophilin D controls mitochondrial pore-dependent Ca(2+)
Frontiers in Oncology | www.frontiersin.org
106.
107.
108.
109.
110.
111.
112.
113.
114.
115.
116.
117.
118.
119.
120.
121.
122.
123.
124.
125.
126.
10
exchange, metabolic flexibility, and propensity for heart failure in mice. J Clin
Invest (2010) 120:3680–7. doi:10.1172/JCI43171
Galluzzi L, Kroemer G. Mitochondrial apoptosis without VDAC. Nat Cell
Biol (2007) 9:487–9. doi:10.1038/ncb0507-487
Biasutto L, Azzolini M, Szabò I, Zoratti M. The mitochondrial permeability transition pore in AD 2016: an update. Biochim Biophys Acta (2016)
1863:2515–30. doi:10.1016/j.bbamcr.2016.02.012
Shanmughapriya S, Rajan S, Hoffman NE, Higgins AM, Tomar D, Nemani
N, et al. SPG7 is an essential and conserved component of the mitochondrial permeability transition pore. Mol Cell (2015) 60:47–62. doi:10.1016/j.
molcel.2015.08.009
Doonan PJ, Chandramoorthy HC, Hoffman NE, Zhang X, Cardenas C,
Shanmughapriya S, et al. LETM1-dependent mitochondrial Ca2+ flux modulates cellular bioenergetics and proliferation. FASEB J (2014) 28:4936–49.
doi:10.1096/fj.14-256453
Jiang D, Zhao L, Clapham DE. Genome-wide RNAi screen identifies
Letm1 as a mitochondrial Ca2+/H+ antiporter. Science (2009) 326:144–7.
doi:10.1126/science.1175145
Mailloux RJ, Harper M-E. Uncoupling proteins and the control of mitochondrial reactive oxygen species production. Free Radic Biol Med (2011)
51:1106–15. doi:10.1016/j.freeradbiomed.2011.06.022
Hoppe UC. Mitochondrial calcium channels. FEBS Lett (2010) 584:1975–81.
doi:10.1016/j.febslet.2010.04.017
Wagner S, De Bortoli S, Schwarzlander M, Szabo I. Regulation of mitochondrial calcium in plants versus animals. J Exp Bot (2016) 67:3809–29.
doi:10.1093/jxb/erw100
Beutner G, Sharma VK, Giovannucci DR, Yule DI, Sheu SS. Identification
of a ryanodine receptor in rat heart mitochondria. J Biol Chem (2001)
276:21482–8. doi:10.1074/jbc.M101486200
Beutner G, Sharma VK, Lin L, Ryu SY, Dirksen RT, Sheu SS. Type 1
ryanodine receptor in cardiac mitochondria: transducer of excitation-metabolism coupling. Biochim Biophys Acta (2005) 1717:1–10. doi:10.1016/j.
bbamem.2005.09.016
Jakob R, Beutner G, Sharma VK, Duan Y, Gross RA, Hurst S, et al. Molecular
and functional identification of a mitochondrial ryanodine receptor in
neurons. Neurosci Lett (2014) 575:7–12. doi:10.1016/j.neulet.2014.05.026
Feng S, Li H, Tai Y, Huang J, Su Y, Abramowitz J, et al. Canonical transient
receptor potential 3 channels regulate mitochondrial calcium uptake. Proc
Natl Acad Sci U S A (2013) 110:11011–6. doi:10.1073/pnas.1309531110
De Pinto V, Messina A, Accardi R, Aiello R, Guarino F, Tomasello MF, et al.
New functions of an old protein: the eukaryotic porin or voltage dependent
anion selective channel (VDAC). Ital J Biochem (2003) 52:17–24.
Granville DJ, Gottlieb RA. The mitochondrial voltage-dependent anion
channel (VDAC) as a therapeutic target for initiating cell death. Curr Med
Chem (2003) 10:1527–33. doi:10.2174/0929867033457214
Halestrap AP, McStay GP, Clarke SJ. The permeability transition pore
complex: another view. Biochimie (2002) 84:153–66. doi:10.1016/
S0300-9084(02)01375-5
Shoshan-Barmatz V, Gincel D. The voltage-dependent anion channel: characterization, modulation, and role in mitochondrial function in cell life and
death. Cell Biochem Biophys (2003) 39:279–92. doi:10.1385/CBB:39:3:279
Shoshan-Barmatz V, Golan M. Mitochondrial VDAC1: function in cell life
and death and a target for cancer therapy. Curr Med Chem (2012) 19:714–35.
doi:10.2174/092986712798992110
Shoshan-Barmatz V, Israelson A, Brdiczka D, Sheu SS. The voltage-dependent
anion channel (VDAC): function in intracellular signalling, cell life and cell
death. Curr Pharm Des (2006) 12:2249–70. doi:10.2174/138161206777585111
Tsujimoto Y, Shimizu S. The voltage-dependent anion channel: an
essential player in apoptosis. Biochimie (2002) 84:187–93. doi:10.1016/
S0300-9084(02)01370-6
Vyssokikh MY, Brdiczka D. The function of complexes between the outer
mitochondrial membrane pore (VDAC) and the adenine nucleotide translocase in regulation of energy metabolism and apoptosis. Acta Biochim Pol
(2003) 50:389–404.
Yuan S, Fu Y, Wang X, Shi H, Huang Y, Song X, et al. Voltage-dependent
anion channel 1 is involved in endostatin-induced endothelial cell apoptosis.
FASEB J (2008) 22:2809–20. doi:10.1096/fj.08-107417
April 2017 | Volume 7 | Article 60
Shoshan-Barmatz et al.
VDAC1 in Ca2+ Signaling and Apoptosis
127. Doran E, Halestrap AP. Cytochrome c release from isolated rat liver mitochondria can occur independently of outer-membrane rupture: possible role
of contact sites. Biochem J (2000) 348 Pt 2:343–50. doi:10.1042/bj3480343
128. Martinou JC, Desagher S, Antonsson B. Cytochrome c release from mitochondria: all or nothing. Nat Cell Biol (2000) 2:E41–3. doi:10.1038/35004069
129. Zalk R, Israelson A, Garty ES, Azoulay-Zohar H, Shoshan-Barmatz V.
Oligomeric states of the voltage-dependent anion channel and cytochrome
c release from mitochondria. Biochem J (2005) 386:73–83. doi:10.1042/
BJ20041356
130. Bernardi P. The permeability transition pore. Control points of a cyclosporin
A-sensitive mitochondrial channel involved in cell death. Biochim Biophys
Acta (1996) 1275:5–9. doi:10.1016/0005-2728(96)00041-2
131. Crompton M. The mitochondrial permeability transition pore and its role in
cell death. Biochem J (1999) 341(Pt 2):233–49. doi:10.1042/bj3410233
132. Betaneli V, Petrov EP, Schwille P. The role of lipids in VDAC oligomerization.
Biophys J (2012) 102:523–31. doi:10.1016/j.bpj.2011.12.049
133. Goncalves RP, Buzhynskyy N, Prima V, Sturgis JN, Scheuring S.
Supramolecular assembly of VDAC in native mitochondrial outer membranes. J Mol Biol (2007) 369:413–8. doi:10.1016/j.jmb.2007.03.063
134. Hoogenboom BW, Suda K, Engel A, Fotiadis D. The supramolecular assemblies of voltage-dependent anion channels in the native membrane. J Mol Biol
(2007) 370:246–55. doi:10.1016/j.jmb.2007.04.073
135. Keinan N, Tyomkin D, Shoshan-Barmatz V. Oligomerization of the
mitochondrial protein voltage-dependent anion channel is coupled to the
induction of apoptosis. Mol Cell Biol (2010) 30:5698–709. doi:10.1128/
MCB.00165-10
136. Shoshan-Barmatz V, Arbel N, Arzoine L. VDAC, the voltage-dependent
anion channel: function, regulation & mitochondrial signaling in cell life and
death. Cell Sci (2008) 4:74–118.
137. Shoshan-Barmatz V, Keinan N, Zaid H. Uncovering the role of VDAC in
the regulation of cell life and death. J Bioenerg Biomembr (2008) 40:183–91.
doi:10.1007/s10863-008-9147-9
138. Shoshan-Barmatz V, Mizrachi D, Keinan N. Oligomerization of the mitochondrial protein VDAC1: from structure to function and cancer therapy. Prog Mol
Biol Transl Sci (2013) 117:303–34. doi:10.1016/B978-0-12-386931-9.00011-8
139. Ujwal R, Cascio D, Chaptal V, Ping P, Abramson J. Crystal packing analysis
of murine VDAC1 crystals in a lipidic environment reveals novel insights
on oligomerization and orientation. Channels (Austin) (2009) 3:167–70.
doi:10.4161/chan.3.3.9196
140. Keinan N, Pahima H, Ben-Hail D, Shoshan-Barmatz V. The role of calcium
in VDAC1 oligomerization and mitochondria-mediated apoptosis. Biochim
Biophys Acta (2013) 1833:1745–54. doi:10.1016/j.bbamcr.2013.03.017
141. Weisthal S, Keinan N, Ben-Hail D, Arif T, Shoshan-Barmatz V. Ca(2+)mediated regulation of VDAC1 expression levels is associated with cell
death induction. Biochim Biophys Acta (2014) 1843:2270–81. doi:10.1016/j.
bbamcr.2014.03.021
142. Huang L, Han J, Ben-Hail D, He L, Li B, Chen Z, et al. A new fungal diterpene
induces VDAC1-dependent apoptosis in Bax/Bak-deficient cells. J Biol Chem
(2015) 290:23563–78. doi:10.1074/jbc.M115.648774
143. Ben-Hail D, Begas-Shvartz R, Shalev M, Shteinfer-Kuzmine A, Gruzman A,
Reina S, et al. Novel compounds targeting the mitochondrial protein VDAC1
inhibit apoptosis and protect against mitochondria dysfunction. J Biol Chem
(2016) 291:24986–5003. doi:10.1074/jbc.M116.744284
144. Abu-Hamad S, Arbel N, Calo D, Arzoine L, Israelson A, Keinan N, et al.
The VDAC1 N-terminus is essential both for apoptosis and the protective
effect of anti-apoptotic proteins. J Cell Sci (2009) 122:1906–16. doi:10.1242/
jcs.040188
145. Arzoine L, Zilberberg N, Ben-Romano R, Shoshan-Barmatz V. Voltagedependent anion channel 1-based peptides interact with hexokinase to prevent its anti-apoptotic activity. J Biol Chem (2009) 284:3946–55. doi:10.1074/
jbc.M803614200
146. Azoulay-Zohar H, Israelson A, Abu-Hamad S, Shoshan-Barmatz V. In
self-defence: hexokinase promotes voltage-dependent anion channel closure
and prevents mitochondria-mediated apoptotic cell death. Biochem J (2004)
377:347–55. doi:10.1042/bj20031465
147. Mathupala SP, Ko YH, Pedersen PL. Hexokinase II: cancer’s double-edged
sword acting as both facilitator and gatekeeper of malignancy when bound
to mitochondria. Oncogene (2006) 25:4777–86. doi:10.1038/sj.onc.1209603
Frontiers in Oncology | www.frontiersin.org
148. Pastorino JG, Hoek JB, Shulga N. Activation of glycogen synthase kinase
3beta disrupts the binding of hexokinase II to mitochondria by phosphorylating voltage-dependent anion channel and potentiates chemotherapy-induced cytotoxicity. Cancer Res (2005) 65:10545–54. doi:10.1158/0008-5472.
CAN-05-1925
149. Pedersen PL, Mathupala S, Rempel A, Geschwind JF, Ko YH. Mitochondrial
bound type II hexokinase: a key player in the growth and survival of many
cancers and an ideal prospect for therapeutic intervention. Biochim Biophys
Acta (2002) 1555:14–20. doi:10.1016/S0005-2728(02)00248-7
150. Pastorino JG, Shulga N, Hoek JB. Mitochondrial binding of hexokinase II
inhibits Bax-induced cytochrome c release and apoptosis. J Biol Chem (2002)
277:7610–8. doi:10.1074/jbc.M109950200
151. Zaid H, Abu-Hamad S, Israelson A, Nathan I, Shoshan-Barmatz V. The voltage-dependent anion channel-1 modulates apoptotic cell death. Cell Death
Differ (2005) 12:751–60. doi:10.1038/sj.cdd.4401599
152. Abu-Hamad S, Zaid H, Israelson A, Nahon E, Shoshan-Barmatz V.
Hexokinase-I protection against apoptotic cell death is mediated via
interaction with the voltage-dependent anion channel-1: mapping the site
of binding. J Biol Chem (2008) 283:13482–90. doi:10.1074/jbc.M708216200
153. Shimizu S, Ide T, Yanagida T, Tsujimoto Y. Electrophysiological study of a
novel large pore formed by Bax and the voltage-dependent anion channel
that is permeable to cytochrome c. J Biol Chem (2000) 275:12321–5.
154. Shimizu S, Narita M, Tsujimoto Y. Bcl-2 family proteins regulate the release
of apoptogenic cytochrome c by the mitochondrial channel VDAC. Nature
(1999) 399:483–7. doi:10.1038/20959
155. Shi Y, Chen J, Weng C, Chen R, Zheng Y, Chen Q, et al. Identification of the
protein-protein contact site and interaction mode of human VDAC1 with
Bcl-2 family proteins. Biochem Biophys Res Commun (2003) 305:989–96.
doi:10.1016/S0006-291X(03)00871-4
156. Westphal D, Dewson G, Czabotar PE, Kluck RM. Molecular biology of Bax
and Bak activation and action. Biochim Biophys Acta (2011) 1813:521–31.
doi:10.1016/j.bbamcr.2010.12.019
157. Anis Y. Involvement of Ca2+ in the apoptotic process – friends or foes.
Pathways (2006) 2:2–7.
158. Gerasimenko JV, Gerasimenko OV, Palejwala A, Tepikin AV, Petersen OH,
Watson AJM. Menadione-induced apoptosis: roles of cytosolic Ca2+ elevations and the mitochondrial permeability transition pore. J Cell Sci (2002)
115:485–97.
159. Boehning D, Patterson RL, Sedaghat L, Glebova NO, Kurosaki T, Snyder SH.
Cytochrome c binds to inositol (1,4,5) trisphosphate receptors, amplifying
calcium-dependent apoptosis. Nat Cell Biol (2003) 5:1051–61. doi:10.1038/
ncb1063
160. Miyamoto S, Howes AL, Adams JW, Dorn GW, Brown JH. Ca2+ dysregulation induces mitochondrial depolarization and apoptosis: role of Na+/
Ca2+ exchanger and AKT. J Biol Chem (2005) 280:38505–12. doi:10.1074/
jbc.M505223200
161. Rong Y, Distelhorst CW. Bcl-2 protein family members: versatile regulators
of calcium signaling in cell survival and apoptosis. Annu Rev Physiol (2008)
70:73–91. doi:10.1146/annurev.physiol.70.021507.105852
162. Giorgi C, Bonora M, Sorrentino G, Missiroli S, Poletti F, Suski JM, et al. p53 at
the endoplasmic reticulum regulates apoptosis in a Ca2+-dependent manner.
Proc Natl Acad Sci U S A (2015) 112:1779–84. doi:10.1073/pnas.1410723112
163. Borahay MA, Kilic GS, Yallampalli C, Snyder RR, Hankins GDV, Al-Hendy
A, et al. Simvastatin potently induces calcium-dependent apoptosis of
human leiomyoma cells. J Biol Chem (2014) 289:35075–86. doi:10.1074/jbc.
M114.583575
164. Hedgepeth SC, Garcia MI, Wagner LE, Rodriguez AM, Chintapalli SV,
Snyder RR, et al. The BRCA1 tumor suppressor binds to inositol 1,4,5-trisphosphate receptors to stimulate apoptotic calcium release. J Biol Chem
(2015) 290:7304–13. doi:10.1074/jbc.M114.611186
165. Jiang N, Kham SK, Koh GS, Suang Lim JY, Ariffin H, Chew FT, et al.
Identification of prognostic protein biomarkers in childhood acute lymphoblastic leukemia (ALL). J Proteomics (2011) 74:843–57. doi:10.1016/j.
jprot.2011.02.034
166. Castagna A, Antonioli P, Astner H, Hamdan M, Righetti SC, Perego P,
et al. A proteomic approach to cisplatin resistance in the cervix squamous
cell carcinoma cell line A431. Proteomics (2004) 4:3246–67. doi:10.1002/
pmic.200400835
11
April 2017 | Volume 7 | Article 60
Shoshan-Barmatz et al.
VDAC1 in Ca2+ Signaling and Apoptosis
167. Sharaf el dein O, Gallerne C, Brenner C, Lemaire C. Increased expression
of VDAC1 sensitizes carcinoma cells to apoptosis induced by DNA
cross-linking agents. Biochem Pharmacol (2012) 83:1172–82. doi:10.1016/j.
bcp.2012.01.017
168. Jung JY, Han CR, Jeong YJ, Kim HJ, Lim HS, Lee KH, et al. Epigallocatechin
gallate inhibits nitric oxide-induced apoptosis in rat PC12 cells. Neurosci Lett
(2007) 411:222–7. doi:10.1016/j.neulet.2006.09.089
169. Voehringer DW, Hirschberg DL, Xiao J, Lu Q, Roederer M, Lock CB, et al.
Gene microarray identification of redox and mitochondrial elements that
control resistance or sensitivity to apoptosis. Proc Natl Acad Sci U S A (2000)
97:2680–5. doi:10.1073/pnas.97.6.2680
170. Cheng SL, Liu RH, Sheu JN, Chen ST, Sinchaikul S, Tsay GJ. Toxicogenomics
of A375 human malignant melanoma cells treated with arbutin. J Biomed Sci
(2007) 14:87–105. doi:10.1007/s11373-006-9130-6
171. Nawarak J, Huang-Liu R, Kao SH, Liao HH, Sinchaikul S, Chen ST, et al.
Proteomics analysis of A375 human malignant melanoma cells in response to
arbutin treatment. Biochim Biophys Acta (2009) 1794:159–67. doi:10.1016/j.
bbapap.2008.09.023
172. Moin SM, Panteva M, Jameel S. The hepatitis E virus Orf3 protein protects
cells from mitochondrial depolarization and death. J Biol Chem (2007)
282:21124–33. doi:10.1074/jbc.M701696200
173. Liu Z, Bengtsson S, Krogh M, Marquez M, Nilsson S, James P, et al.
Somatostatin effects on the proteome of the LNCaP cell-line. Int J Oncol
(2007) 30:1173–9.
174. Tomasello F, Messina A, Lartigue L, Schembri L, Medina C, Reina S, et al.
Outer membrane VDAC1 controls permeability transition of the inner
mitochondrial membrane in cellulo during stress-induced apoptosis. Cell
Res (2009) 19:1363–76. doi:10.1038/cr.2009.98
175. Liu S, Ishikawa H, Tsuyama N, Li FJ, Abroun S, Otsuyama KI, et al. Increased
susceptibility to apoptosis in CD45(+) myeloma cells accompanied by the
increased expression of VDAC1. Oncogene (2006) 25:419–29. doi:10.1038/
sj.onc.1208982
176. Abu-Hamad S, Sivan S, Shoshan-Barmatz V. The expression level of the
voltage-dependent anion channel controls life and death of the cell. Proc Natl
Acad Sci U S A (2006) 103:5787–92. doi:10.1073/pnas.0600103103
177. Ghosh T, Pandey N, Maitra A, Brahmachari SK, Pillai B. A role for voltage-dependent anion channel VDAC1 in polyglutamine-mediated neuronal
cell death. PLoS One (2007) 2:e1170. doi:10.1371/journal.pone.0001170
178. Godbole A, Varghese J, Sarin A, Mathew MK. VDAC is a conserved element
of death pathways in plant and animal systems. Biochim Biophys Acta (2003)
1642:87–96. doi:10.1016/S0167-4889(03)00102-2
179. Shoshan-Barmatz V, Keinan N, Abu-Hamad S, Tyomkin D, Aram L. Apoptosis
is regulated by the VDAC1 N-terminal region and by VDAC oligomerization:
release of cytochrome c, AIF and Smac/Diablo. Biochim Biophys Acta (2010)
1797:1281–91. doi:10.1016/j.bbabio.2010.03.003
180. Mellstrom B, Savignac M, Gomez-Villafuertes R, Naranjo JR. Ca2+-operated
transcriptional networks: molecular mechanisms and in vivo models. Physiol
Rev (2008) 88:421–49. doi:10.1152/physrev.00041.2005
181. Naranjo JR, Mellström B. Ca2+-dependent transcriptional control of Ca2+
homeostasis. J Biol Chem (2012) 287:31674–80. doi:10.1074/jbc.R112.384982
Frontiers in Oncology | www.frontiersin.org
182. Arif T, Vasilkovsky L, Refaely Y, Konson A, Shoshan-Barmatz V. Silencing
VDAC1 expression by siRNA inhibits cancer cell proliferation and
tumor growth in vivo. Mol Ther Nucleic Acids (2014) 3:e159. doi:10.1038/
mtna.2014.9
183. Shoshan-Barmatz V, Ben-Hail D, Admoni L, Krelin Y, Tripathi SS.
The mitochondrial voltage-dependent anion channel 1 in tumor
cells. Biochim Biophys Acta (2015) 1848:2547–75. doi:10.1016/j.
bbamem.2014.10.040
184. Koren I, Raviv Z, Shoshan-Barmatz V. Downregulation of voltage-dependent
anion channel-1 expression by RNA interference prevents cancer cell growth
in vivo. Cancer Biol Ther (2010) 9:1046–52. doi:10.4161/cbt.9.12.11879
185. Arif T, Kerlin Y, Nakdimon I, Benharroch D, Paul A, Dadon-Klein D, et al.
VDAC1 is a molecular target in glioblastoma, with its depletion leading to
reprogrammed metabolism and reversed oncogenic properties. Neuro Oncol
(2017). doi:10.1093/neuonc/now297
186. Marchi S, Pinton P. Alterations of calcium homeostasis in cancer cells. Curr
Opin Pharmacol (2016) 29:1–6. doi:10.1016/j.coph.2016.03.002
187. Cárdenas C, Müller M, McNeal A, Lovy A, Jaňa F, Bustos G, et al. Selective
vulnerability of cancer cells by inhibition of Ca2+ transfer from endoplasmic reticulum to mitochondria. Cell Rep (2016) 14:2313–24. doi:10.1016/j.
celrep.2016.02.030
188. Rimessi A, Patergnani S, Bonora M, Wieckowski MR, Pinton P. Mitochondrial
Ca(2+) remodeling is a prime factor in oncogenic behavior. Front Oncol
(2015) 5:143. doi:10.3389/fonc.2015.00143
189. Sasaki K, Donthamsetty R, Heldak M, Cho YE, Scott BT, Makino A. VDAC:
old protein with new roles in diabetes. Am J Physiol Cell Physiol (2012)
303:C1055–60. doi:10.1152/ajpcell.00087.2012
190. Truong AH, Murugesan S, Youssef KD, Makino A. Mitochondrial ion
channels in metabolic disease. In: Levitan I, Dopico MA, editors. Vascular
Ion Channels in Physiology and Disease. Switzerland: Springer International
Publishing (2016). p. 397–419.
191. Wang DM, Li SQ, Zhu XY, Wang Y, Wu WL, Zhang XJ. Protective effects of
hesperidin against amyloid-beta (Abeta) induced neurotoxicity through the
voltage dependent anion channel 1 (VDAC1)-mediated mitochondrial apoptotic pathway in PC12 cells. Neurochem Res (2013) 38:1034–44. doi:10.1007/
s11064-013-1013-4
192. Gonzalez S, Berthelot J, Jiner J, Perrin-Tricaud C, Fernando R, Chrast R, et al.
Blocking mitochondrial calcium release in Schwann cells prevents demyelinating neuropathies. J Clin Invest (2016) 126:2773. doi:10.1172/JCI84505
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April 2017 | Volume 7 | Article 60