Figure 1.

Signaling pathways engaged by RAS proteins. RAS mutations inhibit GAP-induced GTP hydrolysis, resulting in accumulation of active RAS. Abbreviations denote: GAPs; GTPase-activating proteins, GEFs; guanine nucleotide exchange factors, RalGDS; Ral guanine nucleotide dissociation stimulator, RAL; RAS-related protein, PLD; phospholipase D, RAF; rapidly accelerated fibrosarcoma, MEK; Mitogen-activated protein kinase kinase, ERK; extracellular signal-regulated kinase, PI3K; phosphoinositide 3-kinase, NF-κB; nuclear factor kappa-light-chain-enhancer of activated B cells and mTOR; mammalian target of rapamycin.