RRAS2 (RAS viral (r-ras) oncogene homolog 2) is a member of the Ras like GTPase family that cycle between GTP-bound active and GDP-bound inactive states at the cytoplasmic face of the plasma membrane. RRAS2 is a plasma membrane-associated GTP-binding protein with GTPase activity. RRAS2 is implicated in the pathogenesis of human cancers. Hence, overexpression of active RRAS2 in EpH4 cells induces tumorigenicity through the phosphoinositide 3-kinase, p38 MAPK, and mTOR pathways, as these cells lose their sensitivity to the normal growth inhibitory role of TGF-beta. RRAS2 might transduce growth inhibitory signals across the cell membrane, exerting its effect via an effector shared with the Ras proteins but in an antagonistic manner. RRAS2 is ubiquitously present in all tissues examined, with the highest levels in the heart, placenta, and skeletal muscle. Moderate levels of RRAS2 are found in the lung and liver and low levels in the brain, kidney, and pancreas. RRAS2 deficiencies are linked to ovarian cancer.
