12 Pheromone Response and Signal Transduction during the Mating Process of Saccharomyces cerevisiae

I. INTRODUCTION As an alternative to vegetative (mitotic) proliferation, the two different haploid cell types ( a cells and α cells) of Saccharomyces cerevisiae are able to conjugate (“mate”) to form diploids ( a /α cells). The mating process has supplied an experimental system with which to explore the genetic control of cell-type specification and developmental regulation in eukaryotic cells. The mating process has also allowed investigation of the biochemical basis of intercellular signaling and intracellular signal transduction because conjugation is triggered by the mutual exchange of diffusible peptide pheromones that act through cell-surface G-protein-coupled receptors. Furthermore, study of the mating process has permitted analysis of hormonal regulation of both gene transcription and cell cycle progression, events that lead to a pronounced (but transient) cellular differentiation. Since these subjects were last presented in this forum (Thorner 1981), remarkable progress has been made in understanding the molecular nature of the genes and gene products involved in controlling and mediating this developmental program. Consequently, numerous reviews of various aspects of mating in S. cerevisiae have appeared over the course of the last decade or so (Nasmyth 1982; Sprague et al. 1983a; Rine 1986; Nasmyth and Shore 1987; Cross et al. 1988; Herskowitz 1988, 1989; Marsh and Herskowitz 1988b; Yoshida et al. 1989; Fields 1990; Sprague 1990, 1991a; Blumer and Thorner 1991; Dolan and Fields 1991; Marsh et al. 1991; Rose 1991; Hirsch and Cross 1992; Lipke and Kurjan 1992; Kurjan 1992; Konopka and Fields 1992). Elsewhere in this series are summarized our current picture of...