Cytokinesis is the final step in cell division and is driven by the constriction of the medial actomyosin-based contractile ring (CR) in many eukaryotic cells. In the fission yeast Schizosaccharomyces pombe, the IQGAP-like protein Rng2 is required for assembly and constriction of the CR, and specifically interacts with actin filaments (F-actin) in the CR after anaphase. However, the mechanism that timely activates Rng2 has not yet been elucidated. We herein tested the hypothesis that the cytokinetic function of Rng2 is regulated by phosphorylation by examining phenotypes of a series of non-phosphorylatable and phosphomimetic rng2 mutant strains. In phosphomimetic mutant cells, F-actin in the CR was unstable. Genetic analyses indicated that phosphorylated Rng2 was involved in CR assembly in cooperation with myosin-II, whereas the phosphomimetic mutation attenuated the localization of Rng2 to CR F-actin. The present results suggest that Rng2 is phosphorylated during CR assembly and then dephosphorylated, which enhances the interaction between Rng2 and CR F-actin to stabilize the ring, thereby ensuring secure cytokinesis.

细胞分裂是细胞分裂的最后一步，并受许多真核细胞中基于肌动蛋白内侧收缩环（CR）收缩的驱动。在裂变酵母粟酒裂殖酵母中，IQGAP样蛋白Rng2是CR的组装和收缩所必需的，并且在后期后期与CR中的肌动蛋白丝（F-actin）发生特异性相互作用。但是，尚未阐明及时激活Rng2的机制。我们在本文中通过检验一系列不可磷酸化和拟磷酸化的rng2的表型来检验Rng2的细胞动力学功能受磷酸化调节的假设。突变株。在拟磷酸酶突变细胞中，CR中的F-肌动蛋白不稳定。遗传分析表明，磷酸化的Rng2与肌球蛋白-II协同参与了CR的组装，而拟磷酸酶突变减弱了Rng2对CR F-肌动蛋白的定位。目前的结果表明，Rng2在CR组装过程中被磷酸化，然后被去磷酸化，从而增强Rng2与CR F-肌动蛋白之间的相互作用以稳定环，从而确保安全的胞质分裂。