The Ras superfamily consists of over 150 human members, including orthologs in various organisms. It is divided into five major branches: Ras, Rho, Rab, Ran, and Arf. These small GTPases function as binary molecular switches, regulated by GEFs and GAPs, which control their GDP/GTP cycling. The Ras superfamily proteins share a conserved G domain and have distinct structural and functional characteristics. Lipid modifications, such as farnesylation and geranylgeranylation, are essential for membrane targeting and subcellular localization. The Ras family, including Ras, Rap, R-Ras, Ral, and Rheb, plays critical roles in signaling networks, with Ras being a key oncogene. The Rho family regulates actin organization, cell cycle progression, and gene expression, with RhoA, Rac1, and Cdc42 being the best studied. The Rab family is involved in intracellular vesicular transport, with Rab proteins localizing to specific compartments. The Ran family is crucial for nucleocytoplasmic transport, with Ran-GTP facilitating directional transport. The Arf family regulates vesicular transport, with Arf1 being the best characterized. The Ras superfamily has diverse functions in cellular processes, and their regulation is complex, involving multiple proteins and mechanisms. The superfamily's extensive members, including Gα subunits and up to 50 other human GTPases, highlight the versatility of GTPase switches in controlling cellular processes.The Ras superfamily consists of over 150 human members, including orthologs in various organisms. It is divided into five major branches: Ras, Rho, Rab, Ran, and Arf. These small GTPases function as binary molecular switches, regulated by GEFs and GAPs, which control their GDP/GTP cycling. The Ras superfamily proteins share a conserved G domain and have distinct structural and functional characteristics. Lipid modifications, such as farnesylation and geranylgeranylation, are essential for membrane targeting and subcellular localization. The Ras family, including Ras, Rap, R-Ras, Ral, and Rheb, plays critical roles in signaling networks, with Ras being a key oncogene. The Rho family regulates actin organization, cell cycle progression, and gene expression, with RhoA, Rac1, and Cdc42 being the best studied. The Rab family is involved in intracellular vesicular transport, with Rab proteins localizing to specific compartments. The Ran family is crucial for nucleocytoplasmic transport, with Ran-GTP facilitating directional transport. The Arf family regulates vesicular transport, with Arf1 being the best characterized. The Ras superfamily has diverse functions in cellular processes, and their regulation is complex, involving multiple proteins and mechanisms. The superfamily's extensive members, including Gα subunits and up to 50 other human GTPases, highlight the versatility of GTPase switches in controlling cellular processes.