RAB3A Interacting Protein (RAB3IP)

RAB3IP has several sites for N-glycosylation and phosphorylation. Northern blot analysis detected a 2.1-kb transcript in brain, kidney, heart, placenta, and pancreas, but not in skeletal muscle and liver. Transcripts of 3.8 and 10.2 kb were also detected in brain and kidney.

EST database analysis revealed that RAB3IP was also expressed in retina, fetal thymus, and B-cell germinal centers. In vitro transcription and translation of RAB3IP cDNA resulted in a protein that migrated at an apparent molecular mass of 56 kD by SDS-PAGE. Immunofluorescence analysis of transfected HeLa cells localized RAB32IP in the cytoplasm; however, coexpression of RAB3IP with SSX2 led to colocalization of both proteins in the nucleus.