C-Raf (S471) [B-Raf (S579) /A-Raf (S432) ], Phosphospecific Antibody

The Ras-Raf-MAP kinase signaling pathway is involved in control of cell proliferation and differentiation. The Raf kinase family includes A-Raf, B-Raf, and C-Raf. Each family member has three highly conserved regions (CR1-3) . The N-terminal CR1 contains the Ras-GTP-binding domain. The CR2 contains a negative regulatory serine residue (C-Raf (S259) /B-Raf (S365) ) that may bind 14-3-3 proteins. The CR3 is the catalytic domain that contains phosphorylation sites for Raf-regulating enzymes within two segments, the N-region and the activation segment. Activation of C-Raf involves phosphorylation at many sites including Ser-338, Tyr-341, and Ser-471. The latter site is phosphorylated after EGF stimulation and may be important for MEK interaction in both C-Raf and A-Raf. In B-Raf, multiple phosphorylation sites have been identified, but their specific roles are uncertain. Phosphorylation of Ser-446 may prime B-Raf for activation, and Ser-446 and/or Ser-447 phosphorylation may be critical for B-Raf biological activity during PC12 differentiation. Ser-579 is required for growth factor activation and kinase activity.

This antibody was cross-adsorbed to phospho-C-Raf (Ser-338) peptide before affinity purification using phospho-C-Raf (Ser-471) peptide. The purified antibody detects a band at 74 kDa* corresponding to C-Raf in western blots of human Jurkat cells treated with Calyculin A, but is not observed after lambda phosphatase treatment. This sequence has high homology with similar regions in rat and mouse C-Raf, and has high homology to the conserved sites in B-Raf (Ser-579) and A-Raf (Ser-432) .