CYTOKINESIS AND DIVISION SEPTUM SYNTHESIS IN SCHIZOSACCHAROMYCES POMBE

Abstract

Cytokinesis in Schizosaccharomyces pombe requires the concerted action of a contractile plasma membrane anchored actomyosin ring and concomitant division septum synthesis. The division septum is synthesized in continuation with the external cell wall and is a three layered structure with a central primary septum flanked by secondary septum on either side. The β-1,3-glucan synthase Cps1p / Bgs1p is required for primary septum synthesis and also contributes to maintaining the integrity of the actomyosin ring in collaboration with other proteins. In this study, we identified two essential genes, SPBP22H7.03c (sbg1) and smi1, which support septum synthesis in a temperature-sensitive mutant of Bgs1p synthase. Our results identify a physical interaction of both Sbg1p and Smi1p with Bgs1p. We further characterize both the proteins to understand the role played by each of them in cytokinesis and also to interpret the mechanism by which these two proteins suppress the growth defects of Bgs1p mutant.