B-Raf Proteins and Enzymes

The Raf serine/threonine kinases are effectors of Ras that function as MAP3Ks in the ERK phosphorylation cascade. Mammals express three Raf proteins: Raf-1 (C-Raf); A-Raf; and B-Raf, strongly expressed in fetal brain and adult cerebrum. Mice with a targeted disruption of the B-raf gene die of vascular defects during mid-gestation. B-raf mutations have been found in two-thirds of malignant melanomas, with the single substitution V599E in the kinase domain the most frequent occurrence.