Raf

RAF kinases act downstream of RAS and relay signals through the RAF-MEK-ERK/MAPK cascade to regulate cell growth, survival, and differentiation[1]. Mechanistically, RAF activation depends on phosphorylation, conformational control, membrane recruitment, and kinase-domain dimerization, which provides an allosteric mechanism for catalytic activity[1]. In cancer models, mutant BRAF tumors depend on RAF-MEK-ERK signaling, whereas ATP-competitive RAF inhibitors inhibit ERK signaling in mutant BRAF cells but enhance signaling in wild-type BRAF cells through RAF dimer transactivation[2]. Compared with related isoforms, BRAF has the highest basal kinase activity, while ARAF shows a cell-type-dependent role in MAPK activity and cell migration[3]. CRAF/RAF1 differs further because KRAS-mutant tumor subsets depend on CRAF growth functions, and kinase-dead but not dimer-defective CRAF rescues growth inhibition[4]. For experimental applications, RAF inhibitors therefore serve as pathway probes, but study design should distinguish mutant BRAF inhibition from wild-type RAF dimer activation[2][5].