A novel cholera toxin-sensitive G-protein (Gc) regulating receptor-mediated phosphoinositide signalling in human pituitary clonal cells.
Recent studies have implicated that a GTP-binding protein (G-protein) is involved in the coupling of both CCK-8 and muscarinic cholinergic receptors to phosphoinositidase C (PIC) in the human embryonic pituitary cell line, Flow 9000. Pretreatment of these cells with cholera toxin, but not pertussis toxin, inhibited the stimulation of [3H]inositol phosphate production by CCK-8 and acetylcholine. These inhibitory effects of cholera toxin could not be reproduced by treating the cells with the B-subunit of cholera toxin or cAMP-generating agents such as forskolin. These data suggest the presence of a novel Gc protein which is responsible for receptor-PIC coupling in Flow 9000 cells.
D002772:Cholera Toxin / Q000494:pharmacology*; D002999:Clone Cells; D000242:Cyclic AMP / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000502:physiology*; D006801:Humans; D037342:Pertussis Toxin; D010716:Phosphatidylinositols / Q000502:physiology*; D010902:Pituitary Gland / Q000502:physiology*; D011956:Receptors, Cell Surface / Q000502:physiology*; D011949:Receptors, Cholecystokinin / Q000502:physiology; D011976:Receptors, Muscarinic / Q000502:physiology; D012844:Sincalide / Q000494:pharmacology; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D010716:Phosphatidylinositols; D011956:Receptors, Cell Surface; D011949:Receptors, Cholecystokinin; D011976:Receptors, Muscarinic; D010566:Virulence Factors, Bordetella; D002772:Cholera Toxin; D000242:Cyclic AMP; D037342:Pertussis Toxin; D019204:GTP-Binding Proteins; D012844:Sincalide