Ras proteins are classical members of small GTPases that function as molecular switches by
alternating between inactive GDP-bound and active GTP-bound states. Ras activation is
regulated by guanine nucleotide exchange factors that catalyze the exchange of GDP by
GTP, and inactivation is terminated by GTPase-activating proteins that accelerate the
intrinsic GTP hydrolysis rate by orders of magnitude. In this review, we focus on data that
have accumulated over the past few years pertaining to the conformational ensembles and …