Specific induction of Ca2+ transport activity in MATa cells of Saccharomyces cerevisiae by a mating pheromone, alpha factor

Incubation with a high concentration of a mating pheromone, alpha factor, of Saccharomyces cerevisiae induced the accumulation of Ca2+ ion in MATa cells, but not in MAT alpha or MATa/alpha cells, after a lag of 30-40 min. The alpha factor did not cause a nonspecific lesion of the membrane barrier, but induced Ca2+ transport activity specifically. This induction of Ca2+ transport activity correlated with formation of a projection on the cells, or with localized cell elongation, but not with G1 arrest or agglutinin induction. The increased Ca2+ transport activity was maintained only in the continuous presence of a high concentration of alpha factor and de novo protein synthesis. Kinetic studies of induction of Ca2+ transport by alpha factor and effects of ethylene glycol bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid and Ca2+ ionophore, A23187, on mating suggested an essential role of this physiological reaction in the initiation of sexual conjugation.