One way to regulate the activity of transcription factors is to control the amount of time that they spend in the nucleus. This, in turn, can be modulated by exposing or blocking nuclear-localization and nuclear-export signals. A new regulatory mechanism is now proposed for a transcription factor called NF-AT4, and it seems that two other proteins, calcineurin and Crm1, compete for binding. The outcome of this battle determines whether an import or an export signal is uncovered.
- Patrick G. Hogan
- Anjana Rao