From Wikipedia, the free encyclopedia
|
Complement component 3 |
PDB rendering based on
1c3d. |
|
Available structures |
| 1c3d, 1ghq, 1w2s, 2a73, 2a74, 2b39, 2gox, 2hr0, 2i07, 2ice, 2icf |
|
Identifiers |
| Symbols |
C3; ASP;
CPAMD1 |
| External IDs |
OMIM: 120700 MGI: 88227 HomoloGene: 68031 GeneCards: C3 Gene |
|
|
|
Orthologs |
| Species |
Human |
Mouse |
|
| Entrez |
718 |
12266 |
|
| Ensembl |
n/a |
ENSMUSG00000024164 |
|
| UniProt |
n/a |
Q207D2 |
|
| RefSeq (mRNA) |
NM_000064 |
NM_009778 |
|
| RefSeq (protein) |
NP_000055 |
NP_033908 |
|
| Location (UCSC) |
n/a |
Chr 17:
56.89 - 56.91 Mb |
|
| PubMed search |
[1] |
[2] |
|
Complement component 3, often simply called
C3, is a protein of the immune system. It plays a central role in
the complement system and contributes to
innate immunity. In humans it is encoded on
chromosome 19 by a gene called C3.[1][2]
Function
C3 plays a central role in the activation of complement
system.[3]
Its activation is required for both classical and alternative complement
activation pathways. People with C3 deficiency are susceptible
to bacteria infection.[4][5]
Soluble C3-convertase, also known as C4b2a,
catalyzes the proteolytic cleavage of C3 into C3a and C3b as part of the classical complement
system as well as the mannan-binding lectin
pathway. C3a is an anaphylotoxin, and
C3b serves as an opsonizing
agent. Factor I can cleave C3b into C3c and C3d,
the latter of which plays a role in enhancing B cell responses. In the alternative complement
pathway, C3 is cleaved by iC3Bb, another form of C3-convertase.
Structure
Several crystallographic structures of C3 have been determined
and reveal that this protein contains 13 domains.[6][7][8][9]
Clinical
use
Levels of C3 in the blood may
be measured to support or refute a particular medical diagnosis.
For example, low C3 levels are associated with some types of kidney
disease such as post-infectious glomerulonephritis and shunt
nephritis.
Interactions
Complement component 3 has been shown to interact with Factor H.[10][11]
References
- ^ de Bruijn MH, Fey GH (February 1985). "Human complement component
C3: cDNA coding sequence and derived primary structure".
Proc. Natl. Acad. Sci. U.S.A. 82 (3):
708–12. doi:10.1073/pnas.82.3.708. PMID 2579379. PMC 397115. http://www.pnas.org/content/82/3/708.abstract.
- ^ "Entrez Gene: C3 complement
component 3". http://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene&Cmd=ShowDetailView&TermToSearch=718.
- ^ Sahu A, Lambris JD (April 2001).
"Structure and biology of complement protein C3, a connecting link
between innate and acquired immunity". Immunol. Rev.
180: 35–48. doi:10.1034/j.1600-065X.2001.1800103.x. PMID 11414361.
- ^ Lachmann P (December 1975). "Genetics of the complement
system". J. Med. Genet. 12 (4):
372–7. doi:10.1136/jmg.12.4.372. PMID 768477.
- ^ Matsuyama W, Nakagawa M, Takashima H,
Muranaga F, Sano Y, Osame M (December 2001). "Molecular analysis of
hereditary deficiency of the third component of complement (C3) in
two sisters" ( – Scholar search).
Intern. Med. 40 (12): 1254–8. doi:10.2169/internalmedicine.40.1254. PMID 11813855. http://joi.jlc.jst.go.jp/JST.Journalarchive/internalmedicine1992/40.1254?from=PubMed.
- ^ Janssen BJ, Huizinga EG, Raaijmakers HC,
Roos A, Daha MR, Nilsson-Ekdahl K, Nilsson B, Gros P (September
2005). "Structures of complement component C3 provide insights into
the function and evolution of immunity". Nature
437 (7058): 505–11. doi:10.1038/nature04005. PMID 16177781.
- ^ Janssen BJ, Christodoulidou A, McCarthy A,
Lambris JD, Gros P (November 2006). "Structure of C3b reveals
conformational changes that underlie complement activity".
Nature 444 (7116): 213–6. doi:10.1038/nature05172. PMID 17051160.
- ^ Wiesmann C, Katschke KJ, Yin J, Helmy KY,
Steffek M, Fairbrother WJ, McCallum SA, Embuscado L, DeForge L,
Hass PE, van Lookeren Campagne M (November 2006). "Structure of C3b
in complex with CRIg gives insights into regulation of complement
activation". Nature 444 (7116): 217–20.
doi:10.1038/nature05263. PMID 17051150.
- ^ Fredslund F, Jenner L, Husted LB, Nyborg
J, Andersen GR, Sottrup-Jensen L (August 2006). "The structure of
bovine complement component 3 reveals the basis for thioester
function". J. Mol. Biol. 361 (1): 115–27.
doi:10.1016/j.jmb.2006.06.009. PMID 16831446.
- ^ Soames, C J; Sim R B (Sep. 1997). "Interactions between human complement
components factor H, factor I and C3b". Biochem. J.
(ENGLAND) 326 ( Pt 2): 553–61. ISSN 0264-6021. PMID 9291131.
- ^ Jokiranta, T S; Westin J, Nilsson U R,
Nilsson B, Hellwage J, Löfås S, Gordon D L, Ekdahl K N, Meri S
(Mar. 2001). "Complement C3b
interactions studied with surface plasmon resonance technique".
Int. Immunopharmacol. (Netherlands) 1
(3): 495–506. ISSN 1567-5769. PMID 11367533.
External
links
This article incorporates text from the United States
National Library of Medicine, which is in the public
domain.