Regulation of cytokinesis in the fission yeast Schizosaccharomyces pombe

Abstract

Schizosaccharomyces pombe cells, divide through the use of an actomyosin-based contractile ring. Here I demonstrate that fission yeast heat-shock protein 90 is essential for actomyosin ring assembly. I provide evidence that Swo1p together with the UCS domain protein Rng3p modulates the stability and function of type II myosin Myo2p of fission yeast. In response to perturbation of the actomyosin ring, S. pombe cells delay in a a??cytokinesis-competenta?? state characterized by continuous repair and maintenance of the actomyosin ring and a G2 delay. This checkpoint mechanism requires the function of the Cdc14p-family phosphatase Clp1p and the septation initiation network (SIN) and gives the cell a survival advantage. In response to cytokinetic defects, Clp1p, is retained in the cytoplasm until completion of cell division in a SIN and Rad24p dependent manner. We conclude that Rad24p mediated cytoplasmic retention of Clp1p is important for cell viability upon stress to the division apparatus.