GENETIC ANALYSES OF YEAST PROTEIN-SERINE THREONINE PHOSPHATASES

Protein phosphorylation is an important regulatory phenomenon in yeast s just as in other eukaryotic cells and controls a wide variety of cel lular processes. The importance of protein phosphatases as well as pro tein kinases as key elements in such control is becoming increasingly clear. Over the past four years since the first yeast protein phosphat ase gene was isolated, many more such genes have been described and th e number of genes encoding protein phosphatase catalytic subunits in S accharomyces cerevisiae has comfortably entered double figures. Given the genetic approaches available, yeasts offer powerful systems for ad dressing the cellular roles of these enzymes. This review summarises t he results of genetic studies aimed at determining the functions of pr otein serine/threoninc phosphatases in yeast.