C-raf is the cellular homolog of viral raf gene (v-raf) and encodes a MAP kinase kinase kinase (MAP3K), which functions downstream of the Ras family of membrane associated GTPases. Once activated, C-raf phosphorylates and activates the protein kinases MEK1 and MEK2, which in turn phosphorylate and activate the serine/threonine specific protein kinases, ERK1 and ERK2. These activated ERKs are pleiotropic effectors of cell physiology and play an important role in the control of gene expression involved in the cell division cycle, apoptosis, cell differentiation and cell migration. Mutations in this gene are associated with Noonan syndrome 5 and LEOPARD syndrome 2.
