Cytokinesis in fission yeast: A myosin pas de deux

Cytokinesis in the fission yeast, Schizosaccharomyces pombe consists of two distinct but overlapping events: the assembly and constriction of a cytoki netic actomyosin ring (CAR) and the formation of a cross wall or septum. Th ese two processes must be spatially and temporally coordinated both with ea ch other and with other cell cycle events, most notably spindle formation a nd anaphase chromosome segregation. In fission yeast, the CAR contains two unusual type II myosins, Myo2, encoded by the gene myo(2+), and Myp2, encod ed by myp(2+). The relationship of these two proteins to each other and the ir relative contribution to CAR assembly and contraction is largely unknown . Here we review what is known about the role of each myosin in cytokinesis and present some new information concerning their regulation and possible physical interaction. Microsc. Res. Tech. 49:152-160, 2000. (C) 2000 Wiley- Liss, Inc.