AUTHOR=Osaka Natsuki , Hirota Yoshihisa , Ito Doshun , Ikeda Yoshiki , Kamata Ryo , Fujii Yuki , Chirasani Venkat R. , Campbell Sharon L. , Takeuchi Koh , Senda Toshiya , Sasaki Atsuo T. TITLE=Divergent Mechanisms Activating RAS and Small GTPases Through Post-translational Modification JOURNAL=Frontiers in Molecular Biosciences VOLUME=Volume 8 - 2021 YEAR=2021 URL=https://www.frontiersin.org/journals/molecular-biosciences/articles/10.3389/fmolb.2021.707439 DOI=10.3389/fmolb.2021.707439 ISSN=2296-889X ABSTRACT=
RAS is a founding member of the RAS superfamily of GTPases. These small 21 kDa proteins function as molecular switches to initialize signaling cascades involved in various cellular processes, including gene expression, cell growth, and differentiation. RAS is activated by GTP loading and deactivated upon GTP hydrolysis to GDP. Guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs) accelerate GTP loading and hydrolysis, respectively. These accessory proteins play a fundamental role in regulating activities of RAS superfamily small GTPase