INHIBITION OF MEMBRANE CA2+-ATPASE OF SACCHAROMYCES-CEREVISIAE BY MATING PHEROMONE ALPHA-FACTOR INVITRO

Plasma membrane Ca2+-ATPase of Saccharomyces cerevisiae was solubilized and partially purified by calmodulin-affinity chromatography. The activity of Ca2+-ATPase isolated from MATa cells was inhibited by physiological concentrations of the mating pheromone alpha-factor in a dose-dependent manner. The enzyme prepared from a receptor-deficient sterile mutant cells (DELTA-ste2) was similarly inhibited by alpha-factor, but the enzyme from MAT-alpha cells was resistant to the mating pheromone. We suggest that the inhibition may be involved in the alpha-factor-induced increase of Ca2+ uptake reaction of MATa cells.