Adenylate cyclase and cyclic AMP through the cell cycle of Tetrahymena

Abstract

Adenylate cyclase activity and 3′, 5′ cyclic adenosinemonophosphate (cAMP) have been followed through the heat-synchronized cell cycle of Tetrahymena pyriformis. While the specific activity of adenylate cyclase remained essentially constant throughout the cycle, cAMP oscillated (between 10 and 50 pmoles/mg protein) through two cycles. Minima were observed at each division ( D S border) and maxima at each S G2 border. Each heat shock caused slight temporary reduction in cyclase activity. Further observations suggest to us that adenylate cyclase shows conformational changes in response to temperature-induced alterations and to changes in lipid composition of membranes.