Molecular Mechanism of the Contractile-Ring Assembly in Fission Yeast Cytokinesis

描述（由申请人提供）：在细胞质分裂过程中，细胞成分分裂成两个新的子细胞并在细胞繁殖和细胞分化中起关键作用的收缩环组装机制的理解存在重大空白。我们研究的长期目标是研究酵母、正常体细胞和干细胞以及癌细胞中的细胞分裂。本应用程序的目的是研究分裂酵母细胞分裂过程中收缩环组装的分子机制。分裂酵母裂糖酵母（Schizosaccharomyces pombe）已成为细胞质分裂分析的主要模型系统之一。它不仅遗传上易于处理，有利于显微镜分析，而且具有最小的全测序真核基因组，并像动物细胞一样进行细胞质分裂。由肌动蛋白丝、肌球蛋白- ii马达和bbb30其他蛋白质组成的收缩环对酵母和动物细胞（包括人类）的细胞分裂都是必不可少的。这些蛋白质中的大多数在进化过程中是保守的。该建议的中心假设是细胞动力学收缩环在切割位点从宽频带前体节点逐渐组装成复杂的蛋白质结构。肌动蛋白交联蛋白和Polo激酶在组装过程中起着重要的结构和信号作用。基于坚实的背景研究基础和强大的初步数据，我们将通过调查三个具体目标来验证这一假设：1)阐明anillin Mid1p在节点形成中的作用，并确定其在节点中的结合伙伴；2)建立肌动蛋白交联蛋白Fimbrin和1-actin在节点凝聚成收缩环中的作用；3)探索触发节点形成和节点凝聚成收缩环的信号通路。结合细胞，遗传，生化和共聚焦显微方法将在这些研究中使用。这项研究具有重要意义，因为它将揭示细胞分裂过程中蛋白质如何在收缩环组装过程中协同工作，以及氨酰胺Mid1p如何通过与进化上保守的结构和信号蛋白相互作用来启动收缩环的组装。辨别基本收缩环的组装是理解细胞动力学的重要一步。此外，它将有助于我们了解其他细胞过程中复杂的肌动球蛋白收缩系统。

DESCRIPTION (provided by applicant): A significant gap exists in understanding the mechanism of contractile-ring assembly during cytokinesis, which partitions cellular constituents into two new daughter cells and plays a crucial role in cell reproduction and cell differentiation. The long-term goal of our research is to investigate cytokinesis in yeast, in normal somatic and stem cells, as well as in cancer cells. The objective of this application is to investigate the molecular mechanism of the assembly of the contractile ring in fission yeast cytokinesis. The fission yeast Schizosaccharomyces pombe has emerged as one of the leading model systems for the analysis of cytokinesis. Not only is it genetically tractable and favorable for microscopic analysis, but it also has the smallest fully sequenced eukaryotic genome and carries out cytokinesis much like animal cells. Contractile rings consisting of actin filaments, myosin-II motors, and >30 other proteins are essential for cytokinesis in both yeast and animal cells, including humans. The majority of these proteins are conserved during evolution. The central hypothesis of this proposal is that the cytokinetic contractile ring assembles progressively at the cleavage site from a broad band of precursor nodes into a complex protein structure. Actin cross-linking proteins and Polo kinase play essential structural and signaling roles during the assembly. Based on a solid foundation of background research and strong preliminary data, this hypothesis will be tested by investigating three specific aims: 1) Elucidate the roles of the anillin Mid1p in node formation and identify its binding partners in the nodes; 2) Establish the roles of actin cross-linking proteins Fimbrin and 1-actinin in coalescing the nodes into the contractile ring; 3) Explore the signaling pathways that trigger node formation and node condensation into the contractile ring. A combination of cellular, genetic, biochemical, and confocal microscopic approaches will be employed in these studies. This research is significant because it will reveal how proteins work together during contractile-ring assembly in cytokinesis, and how the anillin Mid1p initiates the assembly of the contractile ring by interacting with evolutionarily conserved structural and signaling proteins. Discerning the assembly of the essential contractile-ring is an important step towards understanding cytokinesis. Additionally, it will help us understand complex actomyosin contractile systems in other cellular processes.