ROLE OF MYOGEF AND ITS INTERACTING PARTNERS IN THE REGULATION OF CYTOKINESIS

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 一个细胞分裂为两个子细胞，即胞质分裂，是生物学中的一个基本过程。在胞质分裂期间，沟内移被认为是由肌动蛋白和肌球蛋白细丝之间的相互作用产生的机械力提供动力，肌动蛋白和肌球蛋白细丝在后期和末期细胞中形成收缩环。大量的证据表明，中央纺锤体是定位收缩环的重要因素之一。然而，潜在的机制仍然不清楚：肌球蛋白II如何集中在卵裂沟中，以响应中央纺锤体的组装，一组反平行的微管在后期细胞中被捆绑。 我们已经确定了肌球蛋白相互作用的GEF鸟嘌呤核苷酸交换因子（MyoGEF），这是能够结合到非肌肉肌球蛋白II，集中在裂解沟，并激活小GTdR蛋白RhoA。此外，MyoGEF与另一种蛋白质相互作用，称为MyoGEF相互作用的中央纺锤体蛋白（MICSP），其集中在后期细胞的中央纺锤体。因此，我们假设，MyoGEF，RhoA，和非肌肉肌球蛋白II组装在卵裂沟作为一个功能单位，这是锚定的中央纺锤体通过MyoGEF-MICSP相互作用。为了验证这一假设，我们将使用生物化学，细胞生物学和分子生物学的组合，以哺乳动物细胞为模型，以：1）阐明MyoGEF和非肌肉肌球蛋白II之间的相互作用。2)阐明MyoGEF和MICSP之间的相互作用。3)确定MyoGEF在胞质分裂调节中的重要性。4)定义MICSP集中在中心主轴的结构基础。该提案中概述的研究的成功完成有望为癌症中细胞分裂如何出错提供见解，并为预防和治疗癌症提供潜在的分子策略。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Division of a cell into two daughter cells, i.e. cytokinesis, is a fundamental process in biology. During cytokinesis, furrow ingression is believed to be powered by the mechanical force generated by the interaction between actin and myosin filaments, which form a contractile ring in anaphase and telophase cells. A body of evidence has implicated the central spindle as one of the important factors in positioning the contractile ring. However, the underlying mechanism is still unclear: how does myosin II concentrate at the cleavage furrow in response to the assembly of the central spindle, a set of antiparallel microtubules that become bundled in anaphase cells. We have identified a myosin-interacting GEF guanine nucleotide exchange factor (MyoGEF), which is capable of binding to nonmuscle myosin II, concentrating at the cleavage furrow, and activating the small GTPase protein RhoA. Additionally, MyoGEF interacts with another protein, called MyoGEF-interacting central spindle protein (MICSP), which concentrates at the central spindle in anaphase cells. We therefore hypothesize that MyoGEF, RhoA, and nonmuscle myosin II are assembled at the cleavage furrow as a functional unit, which is anchored to the central spindle via MyoGEF-MICSP interaction. To test this hypothesis, we will use a combination of biochemistry, cell biology, and molecular biology, with mammalian cells as a model, to: 1) Elucidate the interaction between MyoGEF and nonmuscle myosin II. 2) Elucidate the interaction between MyoGEF and MICSP. 3) Determine the importance of MyoGEF in the regulation of cytokinesis. 4) Define the structural basis for MICSP to concentrate at the central spindle. The successful completion of the research outlined in this proposal is expected to provide insights into how cell division goes awry in cancer as well as to provide potential molecular strategies for the prevention and treatment of cancer.