Mechanisms of formation and destruction of the contractile ring during cytokinesis

胞质分裂过程中收缩环的形成和破坏机制

基本信息

批准号：
10213101
负责人：
MABUCHI Issei
金额：
$ 17.54万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research on Priority Areas
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2001
项目状态：
已结题

项目摘要

We analyzed mechanism of formation of the contractile ring using various cells. In fission yeast cells, the contractile ring is formed from F-actin cables which accumulate at the medial region of the cell during nuclear division. The aster-like structure consisting of F-actin cables and the leading cable which elongates from the structure are important in this process. Cdcl2 plays a role in elongation of the leading cable, while Cdc15 plays a role in the fusion of the F-actin cables to the leading cable. We also analyzed function of Rho proteins in fission yeast, and found a novel G-protein Rho3. Rho3 is localized to the cell membrane .It was found that a novel formin family protein For3 is present downstream of either Rho3 or Cdc42. Rho3 and For3 controls both actin cytoskeleton and microtubules, and thereby regulate shape of the cell and position of cytokinesis. Cla4(PAK) and Bni1 (formin) cooperatively function in regulation of the septin ring in budding yeast. F-actin plays an impo … More rtant role in this process. In Tetrahymena, dimeric EF1a bundles F-actin. Ca/calmodulin dissociates this EF1a dimer and thus inhibit the bundling of F-actin. Tetrahymena fimbrin binds and bundles F-actin in a Ca-insensitive manner. It is localized to the cleavage furrow. We found that actin is less concentrated in the cortex near the centrosome while concentrated in the cortex away from it, where the furrow is formed, in the fourth division in sea urchin embryos. Role of microtubules in formation of the contractile ring in Xenopus eggs was analyzed. Disruption of microtubules by microtubule poisons did not interfere with contraction of the contractile ring, but interfered with its formation. We also found that the microtubules emanated from the both poles link with each other beneath the cleavage furrow. We tested a possibility that Ca ions play a role in cleavage signaling by analyzing Ca release around the cleavage furrow. Neither Ca waves nor small Ca releases such as Ca puffs or Ca blips were found at the leading edge of the cleavage furrow. Rho-kinase in HeLa cells binds to filamin A. Thus, it is possible that these proteins co-localize in the contractile ring. Less

我们使用各种细胞分析了收缩环形成的机理。在裂变酵母细胞中，收缩环是由核分裂过程中在细胞中间区域积聚的F-肌动蛋白电缆形成的。在此过程中，由F-肌动蛋白电缆和从结构上延伸的前导电缆组成的星状结构在此过程中很重要。 CDCL2在领先电缆的伸长率中起作用，而CDC15在F-肌动蛋白电缆与领先电缆的融合中起作用。我们还分析了Rho蛋白在裂变酵母中的功能，并发现了一种新型的G蛋白Rho3。 Rho3位于细胞膜。发现新型的formin家族蛋白for3存在于Rho3或Cdc42的下游。 Rho3和For3控制肌动蛋白细胞骨架和微管，从而调节细胞的形状和细胞因子的位置。 CLA4（PAK）和BNI1（FORMIN）在发芽酵母中的septin环调节中起作用。 F-肌动蛋白在此过程中起着重要的作用。在四膜虫中，二聚体EF1A捆绑F-肌动蛋白。 Ca/钙调蛋白解离该EF1A二聚体，从而抑制F-肌动蛋白的束。四膜膜纤维蛋白以ca不敏感的方式结合和束F-肌动蛋白。它位于乳沟沟中。我们发现，肌动蛋白在中心体附近的皮质中少于浓缩，而将肌肉集中在远离的皮质中，在那里形成犁沟，在海胆胚胎中的第四个分裂中。分析了微管在爪蟾卵中收缩环形成中的作用。微管毒物对微管的破坏不会干扰收缩环的收缩，而是干扰其形成。我们还发现，从两个杆子散发出的微管在裂解沟下彼此连接。我们测试了CA离子通过分析裂解沟周围的CA释放在裂解信号传导中发挥作用的可能性。在裂解沟的前缘都没有发现Ca波和小Ca释放，例如Ca泡芙或Ca Blip。 HeLa细胞中的Rho-激酶与丝蛋白A结合。这些蛋白可能会在收缩环中共定位。较少的