Mastoparan inhibits phosphoinositide hydrolysis via pertussis toxin-insensitive [corrected] G-protein in human astrocytoma cells.
Mastoparan inhibited [3H]inositol phosphate accumulation induced by carbachol as well as cyclic AMP accumulation induced by isoproterenol in 1321N1 human astrocytoma cells. Mastoparan inhibited GTP gamma S-induced, but not Ca2(+)-induced, [3H]inositol phosphate accumulation in membrane preparations with an IC50 of approximately 10 microM. The inhibitory effect of mastoparan on carbachol-induced [3H]inositol phosphate accumulation was resistant to pertussis toxin (IAP) treatment in intact cells. These results suggest that mastoparan inhibits phospholipase C in human astrocytoma cells via a GTP binding protein, which is not a substrate for IAP.
Nakahata
N
N
Department of Pharmacology, Fukushima Medical College, Japan.
Abe
M T
MT
Matsuoka
I
I
Nakanishi
H
H
D001254:Astrocytoma / Q000201:enzymology / Q000378:metabolism*; D001514:Bee Venoms / Q000494:pharmacology*; D002118:Calcium / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D019204:GTP-Binding Proteins / Q000494:pharmacology*; D006160:Guanosine Triphosphate / Q000037:antagonists & inhibitors / Q000494:pharmacology; D006801:Humans; D006868:Hydrolysis; D007295:Inositol Phosphates / Q000378:metabolism; D036341:Intercellular Signaling Peptides and Proteins; D010455:Peptides; D037342:Pertussis Toxin; D010716:Phosphatidylinositols / Q000378:metabolism*; D014407:Tumor Cells, Cultured / Q000187:drug effects; D010738:Type C Phospholipases / Q000037:antagonists & inhibitors; D010566:Virulence Factors, Bordetella / Q000494:pharmacology; D014862:Wasp Venoms / Q000037:antagonists & inhibitors / Q000494:pharmacology*
D001514:Bee Venoms; D007295:Inositol Phosphates; D036341:Intercellular Signaling Peptides and Proteins; D010455:Peptides; D010716:Phosphatidylinositols; D010566:Virulence Factors, Bordetella; D014862:Wasp Venoms; C037500:mastoparan; D006160:Guanosine Triphosphate; D000242:Cyclic AMP; D037342:Pertussis Toxin; D010738:Type C Phospholipases; D019204:GTP-Binding Proteins; D002118:Calcium