Cell polarity in yeast

Abstract

Abstract Eukaryotic cells respond to intracellular and extracellular cues to direct cell growth and division. Selecting sites of polarized growth and division is crucial for the development of both unicellular and multicellular organisms. The two yeasts Saccharomyces cerevisiae (budding yeast) and Schizosaccharomyces pombe (fission yeast) have rigid cell walls. Cellular polarization targets secretion of cell wall and other materials to restricted areas in the cell. As a result, cell polarity in these yeasts directly underlies cellular morphogenesis. Both budding and fission yeast establish cell polarity at several stages for growth, cytokinesis, mating, and sporulation. Thus, they are useful model organisms for studying various aspects of cell polarity. In recent years, many regulatory and cytoskeletal components important for directing and establishing polarity have been identified, and molecular mechanisms underlying polarity development in yeast have been elucidated. Key signalling pathways that regulate polarization during the cell cycle and mating response have been described. Since many of the components important for polarized cell growth are conserved in other organisms, the basic mechanisms mediating cell polarity are likely to be universal among eukaryotes.