Members of the Rab protein family are nontransforming monomeric GTP-binding proteins of the Ras superfamily that contain 4 highly conserved regions involved in GTP binding and hydrolysis. Rab proteins are prenylated, membrane-bound proteins involved in vesicular fusion and trafficking; see MIM 179508.[supplied by OMIM, Apr 2006] see less Members of the Rab protein family are nontransforming monomeric GTP-binding proteins of the Ras superfamily that contain 4 highly conserved regions involved in GTP binding and hydrolysis. Rab proteins are prenylated, membrane-bound proteins involved in vesicular fusion and trafficking; see MIM 179508.[supplied by OMIM, Apr 2006]