Cell polarization directed by extracellular cues in yeast.

Many cell types are able to generate cellular asymmetry, or polarize, in response to chemical gradients in the environment. The question of how external signals influence cell polarity requires an understanding of how a chemoattractant signaling pathway leads to organization of the cytoskeleton. Studies of polarizing yeast cells and other chemotactic cells indicate that similar molecules and pathways may be involved in these diverse systems. This review will focus on cell polarization in response to extracellular signals during yeast mating. First, the phenomenon of cell polarization during yeast mating will be described. Then the extensive work on cell polarization during yeast budding will be reviewed, and a model for mating cell polarity will be presented. Finally, eucaryotic chemotaxis will be briefly summarized, and the similarities to polarization during yeast mating will be discussed.