Molecular characterization of helodermin-preferring VIP receptors in SUP T1 lymphoma cells: evidence for receptor glycosylation.
Cross-linking of [125I]helodermin to human SUP-T1 lymphoblasts with bis[2-(succinimidooxycarbonyloxy)ethyl]sulfone (BSOCOES) revealed a 63 K binding protein. This cross-linking was inhibited by helodermin and VIP. In cells submitted for 3-4 days to 0.2 microgram/ml tunicamycin, the Mr of an increasing proportion of helodermin-preferring receptors was reduced to 50 K and the total number of receptors was decreased by about 50%, without alteration in binding affinity and specificity. In parallel, the VIP-mediated adenylate cyclase stimulation was reduced by 30% with no change in NaF-, Gpp[NH]p-, and PGE1-stimulations. We conclude that a proper N-glycosylation of helodermin-preferring VIP receptors is required for normal receptor targeting and turnover but not for ligand binding and adenylate cyclase coupling.
Gourlet
P
P
Department of Biochemistry and Nutrition, Medical School, Université Libre de Bruxelles, Belgium.
Robberecht
P
P
Christophe
J
J
D000262:Adenylyl Cyclases / Q000737:chemistry; D000595:Amino Acid Sequence; D002460:Cell Line; D003432:Cross-Linking Reagents; D004789:Enzyme Activation; D006031:Glycosylation; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D008223:Lymphoma / Q000737:chemistry* / Q000201:enzymology; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry*; D011964:Receptors, Gastrointestinal Hormone / Q000737:chemistry*; D018005:Receptors, Vasoactive Intestinal Peptide; D013388:Succinimides / Q000737:chemistry; D014407:Tumor Cells, Cultured; D014660:Vasoactive Intestinal Peptide / Q000737:chemistry*; D014688:Venoms / Q000737:chemistry*
D003432:Cross-Linking Reagents; D036341:Intercellular Signaling Peptides and Proteins; D010455:Peptides; D011964:Receptors, Gastrointestinal Hormone; D018005:Receptors, Vasoactive Intestinal Peptide; D013388:Succinimides; D014688:Venoms; D014660:Vasoactive Intestinal Peptide; C011683:bis(2-(succinimidooxycarbonyloxy)ethyl)sulfone; C040442:heliodermin; D000262:Adenylyl Cyclases