Effect of anticalmodulin drugs on the action of yeast alpha factor pheromone.

Saccharomyces cerevisiae alpha factor pheromone arrest growth of cells of the a mating type (MAT a) at the G1 phase of the cell cycle. When treatment of MAT a cells with alpha factor was carried out in the presence of anticalmodulin drugs, trifluoperazine or chlorpromazine, the extent of cell growth arrest induced by alpha factor was reduced or even became undetectable. These results lend support to the hypothesis that calmodulin plays a role as mediator in the action of alpha factor on MAT a cells.