Raf-1

Raf-1 (CRAF), encoded by RAF1, is the archetypal MAP kinase kinase kinase of the RAS-RAF-MEK-ERK cascade. Recruited to activated RAS at the plasma membrane, Raf-1 undergoes dephosphorylation, dimerization with BRAF and activating phosphorylation before phosphorylating MEK1 and MEK2. Its N-terminal regulatory region binds 14-3-3 proteins and is targeted by phosphorylation events that restrain or release kinase activity. Germline RAF1 mutations cause Noonan syndrome and LEOPARD syndrome, and somatic Raf-1 deregulation contributes to MAPK pathway activation in cancers, sustaining continued pharmacological interest.