Ras

Regulates cell growth through serine–threonine protein kinases

Rho

Reorganizes cytoskeleton through serine–threonine protein kinases

Arf

Activates the ADP-ribosyltransferase of the cholera toxin A subunit; regulates vesicular trafficking pathways; activates phospholipase D

Rab

Plays a key role in secretory and endocytotic pathways

Ran

Functions in the transport of RNA and protein into and out of the nucleus