The Rab3-interacting molecule RIM is expressed in pancreatic beta-cells and is implicated in insulin exocytosis.
The putative Rab3 effector RIM (Rab3-interacting molecule) was detected by Northern blotting, RT-PCR and Western blotting in native pancreatic beta-cells as well as in the derived cell lines INS-1E and HIT-T15. RIM was localized on the plasma membrane of INS-1E cells and beta-cells. An involvement of RIM in insulin exocytosis was indicated by transfection experiments of INS-1E cells with the Rab3 binding domain of RIM. This domain enhanced glucose-stimulated secretion in intact cells and Ca(2+)-stimulated exocytosis in permeabilized cells. Co-expression of Rab3A reversed the effect of RIM on exocytosis. These results suggest an implication of RIM in the control of insulin secretion.
Iezzi
M
M
Division de Biochimie Clinique, Centre Médical Universitaire, Departement de Médecine Interne, Université de Genevé, Switzerland.
Regazzi
R
R
Wollheim
C B
CB
D000818:Animals; D002460:Cell Line; D002462:Cell Membrane / Q000737:chemistry; D006224:Cricetinae; D005089:Exocytosis; D019204:GTP-Binding Proteins; D015870:Gene Expression; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007340:Insulinoma; D007515:Islets of Langerhans / Q000378:metabolism* / Q000648:ultrastructure; D051379:Mice; D009419:Nerve Tissue Proteins / Q000032:analysis / Q000235:genetics* / Q000502:physiology*; D010190:Pancreatic Neoplasms; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014407:Tumor Cells, Cultured; D020692:rab3 GTP-Binding Proteins / Q000378:metabolism
D007328:Insulin; D009419:Nerve Tissue Proteins; C491492:RIMS1 protein, human; C107293:Rim protein, mammalian; C491490:Rims1 protein, mouse; C491489:Rims1 protein, rat; D019204:GTP-Binding Proteins; D020692:rab3 GTP-Binding Proteins