title: Adenylate cyclase inhibition and GTPase stimulation by somatostatin in S49 lymphoma cyc- variants are prevented by islet-activating protein.
abstract: cyc--Variants of S49 lymphoma cells are defective in the stimulatory guanine nucleotide site of the adenylate cyclase but contain an inhibitory site. Treatment of cyc- cells with islet-activating protein (IAP), which causes ADP-ribosylation of an Mr 40 000 polypeptide in cyc- membranes, abolishes adenylate cyclase inhibition by GTP and the peptide hormone, somatostatin, but not that induced by GTP gamma S. Furthermore, somatostatin-induced stimulation of GTP hydrolysis is lost. Thus, the data indicate that IAP interferes with the adenylate cyclase system by an action at the inhibitory guanine nucleotide site.
mesh_terms: D037361:Adenylate Cyclase Toxin; D000067956:Adenylyl Cyclase Inhibitors; D000818:Animals; D001426:Bacterial Proteins / Q000494:pharmacology*; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation / Q000187:drug effects; D020558:GTP Phosphohydrolases / Q000378:metabolism*; D008223:Lymphoma / Q000201:enzymology*; D051379:Mice; D009374:Neoplasms, Experimental / Q000201:enzymology; D037342:Pertussis Toxin; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism*; D013004:Somatostatin / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D010566:Virulence Factors, Bordetella
chemical_list: D037361:Adenylate Cyclase Toxin; D000067956:Adenylyl Cyclase Inhibitors; D001426:Bacterial Proteins; D010566:Virulence Factors, Bordetella; D013004:Somatostatin; D037342:Pertussis Toxin; D010744:Phosphoric Monoester Hydrolases; D020558:GTP Phosphohydrolases