BRCA1-associated protein (BRAP)

Negatively regulates MAP kinase activation by limiting the creation of Raf/MEK complexes likely by inactivation of the KSR1 scaffold protein. Also functions as a Ras responsive E3 ubiquitin ligase that, on activation of Ras, is altered by auto- polyubiquitination leading to the release of inhibition of Raf/MEK complex formation.

May also act as a cytoplasmic retention protein with a role in regulating nuclear transport. .