Impedes Mitogenic Signal Propagation (IMP)

IMP is a RAS-responsive E3 ubiquitin ligase that, on activation of RAS, is modified by autopolyubiquitination, which releases the inhibition of RAF-MEK complex formation. Thus, RAS activates the MAP kinase cascade through simultaneous dual effector interactions: induction of RAF kinase activity and derepression of RAF-MEK complex formation. IMP depletion results in increased stimulus-dependent MEK activation without alterations in the timing or duration of the response.IMP functions as a threshold modulator, controlling sensitivity of the cascade to stimulus and providing a mechanism to allow adaptive behavior of the cascade in chronic or complex signaling environments.BRAP plays a role in the cytoplasmic translocation of p21 during monocyte differentiation.