Novel GTP-binding proteins in plasma membranes and zymogen granule membranes from rat pancreas and in pancreatic AR 4-2J cell membranes.
Photoaffinity labelling with [alpha-32P]GTP allowed to detect a 54 kDa GTP-binding protein in rat pancreatic plasma membranes and in pancreatic AR 4-2J cell membranes. Like the 42 and 48 kDa Gs alpha subunits and the 41 kDa Gi alpha subunit, this protein was absent from zymogen granule membranes. Contrastingly, a new 28 kDa GTP-binding protein (detected by [alpha-32P]GTP binding on immobilized proteins) and a 25 kDa protein (ADP-ribosylated by botulinum toxin D) were found in all three membrane preparations. This is to our knowledge the first report on GTP-binding proteins in zymogen granule membranes.
Lambert
M
M
Department of Biochemistry and Nutrition, Medical School, Université Libre de Bruxelles, Belgium.
Bui
N D
ND
Christophe
J
J
D000818:Animals; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D003432:Cross-Linking Reagents / Q000378:metabolism; D003594:Cytoplasmic Granules / Q000201:enzymology*; D003603:Cytotoxins / Q000494:pharmacology; D004792:Enzyme Precursors / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D010179:Pancreas / Q000187:drug effects / Q000378:metabolism*; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism*; D051381:Rats
D003432:Cross-Linking Reagents; D003603:Cytotoxins; D004792:Enzyme Precursors; D008565:Membrane Proteins; D006160:Guanosine Triphosphate; D011065:Poly(ADP-ribose) Polymerases; D019204:GTP-Binding Proteins