"To address a possible role of mutant C-RAF proteins in the constitutive phosphorylation of ERK1/2, kinase assays were done with Myc-tagged C-RAF proteins immunoprecipitated from transiently transfected Cos-7 cells. Strong constitutive kinase activity was shown for S427GC-RAF whereas I448VC-RAF did not significantly differ from wt C-RAF (Fig. 3A)."
"Mitogen-activated protein (MAP) kinases comprise a family of ubiquitous proline-directed, protein-serine/threonine kinases, which participate in signal transduction pathways that control intracellular events including acute responses to hormones and major developmental changes in organisms. MAP kinases lie in protein kinase cascades. This review discusses the regulation and functions of mammalian MAP kinases. Nonenzymatic mechanisms that impact MAP kinase functions and findings from gene disruption studies are highlighted. Particular emphasis is on ERK1/2."