Cytokinesis and the contractile ring in fission yeast.

The fission yeast Schizosaccharomyces pombe provides a genetic model system for the study of cytokinesis. As in many eukaryotes, cell division in the fission yeast requires an actin-myosin-based contractile ring. Numerous components of the contractile ring that function in ring assembly, positioning and contraction have been characterized. Many of these proteins are evolutionarily conserved, suggesting that common molecular mechanisms may govern aspects of eukaryotic cell division. Recent advances in the assembly and placement of the contractile ring are discussed. In particular, major findings have been made in the characterization of myosins in cytokinesis, and in how the cell division site may be positioned by the nucleus.