Ras Like, Estrogen Regulated, Growth Inhibitor (RERG)

RERG shares 44 to 45% amino acid identity with RIT, RRAS2, MRAS, RIT2, and RAP1B. RERG contains an ala12 residue corresponding to gly12 of Ki-Ras (KRAS), which is where a gly12-to-ala substitution causes constitutive Ki-Ras activation. RERG has no C-terminal prenylation motif. Northern blot analysis detected a 2.6-kb transcript with highest expression in human heart, kidney, and pancreas, and lower expression in brain, placenta, lung, liver, and skin. EST database analysis supported an ubiquitous pattern of expression. Immunofluorescence microscopy localized RERG in a uniform diffuse pattern in the cytoplasm of MCF-7 breast tumor cells, and biochemical fractionation and Western blot analysis showed RERG was present in the cytosolic fraction of MCF-7 cells.