RAB Interacting Factor (RABIF)

The Sec4/Rab-related small GTP-binding proteins are involved in the regulation of intracellular vesicular transport. Mss4 stimulates GTP-GDP exchange in Sec4 and Rab and binds to a subset of genetically related Rab proteins.The gene encodes a 123-amino acid polypeptide that requires zinc for stability.

MSS4 is expressed as 3 differently sized mRNAs, probably due to alternative polyadenylation signals. The transcripts are present at barely detectable levels in healthy pancreas, but at much higher levels in pancreatic and other cancer tissues.MSS4 bound specifically to integrins containing an aromatic amino acid before the first lysine of the conserved motif. These integrins included alpha-2 , alpha-3A, alpha-3B, alpha-5, and alpha-6A.