Raf-1 (synonym C-Raf; RAF) encodes for a serine/threonine protein kinase that is activated by RAS and in turn phosphorylates and activates Map/Erk Kinase (MEK) one-half which then phosphorylates extracellular-regulated kinase (ERK). This signaling pathway is a key mediator of cell proliferation, survival, differentiation, and migration.
First discovered as mutant retroviral transforming agent, v-raf, Raf is a dual serine/threonine protein kinase. There are three forms of Raf, with Raf-1 being the most studied one. Other forms, A-Raf and B-RAF, are not as ubiquitously expressed. A-Raf is primarily in muscles and B-Raf is primarily in neurologic tissue. In contrast, Raf-1 is expressed in multiple tissues.
Raf-1 is 73 kDa and consists of 648 amino acids (aa). Four protein domains have been defined for Raf-1, including an N-terminal RBD (Ras-binding domain) (aa 56–131), a cysteine-finger region (aa 138–184) (CR1), a...