Inhibition of adenylate cyclase by transglutaminase-catalyzed reactions in pigeon erythrocyte ghosts.
We report the occurrence in pigeon erythrocytes of a soluble Ca2+-dependent transglutaminase (TGase) activity. The effect of the erythrocyte ghost protein modifications, determined by TGase-catalyzed reactions, on adenylate cyclase, phospholipid methyltransferase I and II activities and on the lipidic matrix fluidity of the membrane was investigated by using a purified guinea pig liver TGase preparation. The results showed a significant inhibitory effect of such modifications both on the basal and on the variously stimulated (by NaF, Gpp(NH)p alone or in the presence of 1-isoproterenol) adenylate cyclase activity. By contrast, both the phospholipid methylation and the fluidity of the lipidic matrix of the membrane were unaffected by TGase-mediated reactions. These data suggest a new possible inhibitory mechanism of the cyclic AMP synthesis which might be triggered by the enhancement of the cytosolic Ca2+ concentration.
D000255:Adenosine Triphosphate / Q000097:blood; D000067956:Adenylyl Cyclase Inhibitors; D000262:Adenylyl Cyclases / Q000097:blood*; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002250:Carbon Radioisotopes; D002364:Caseins / Q000097:blood; D010856:Columbidae; D004910:Erythrocyte Membrane / Q000201:enzymology*; D007700:Kinetics; D008780:Methyltransferases / Q000097:blood; D050941:Phosphatidyl-N-Methylethanolamine N-Methyltransferase; D050918:Phosphatidylethanolamine N-Methyltransferase; D010761:Phosphorus Radioisotopes; D013095:Spermidine / Q000097:blood; D011503:Transglutaminases / Q000097:blood*
D000067956:Adenylyl Cyclase Inhibitors; D002250:Carbon Radioisotopes; D002364:Caseins; D010761:Phosphorus Radioisotopes; D000255:Adenosine Triphosphate; D008780:Methyltransferases; D050918:Phosphatidylethanolamine N-Methyltransferase; D050941:Phosphatidyl-N-Methylethanolamine N-Methyltransferase; D011503:Transglutaminases; D000262:Adenylyl Cyclases; D002118:Calcium; D013095:Spermidine