Roles of MyoGEF in cytokinesis

MyoGEF 在胞质分裂中的作用

• 批准号: 8101551
• 负责人: QIZE WEI
• 金额: $ 4.68万
• 依托单位: KANSAS STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-08-01 至 2012-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8101551
• 关键词: Anaphase; Applications Grants; Binding; Biochemical; Biochemistry; Biological Assay; Cell Proliferation; Cells; Cellular biology; Centrosome; Characteristics; Clear Cell; Cytokinesis; Data; Docking; Epithelial; GTPase-Activating Proteins; Genomic Instability; Germ Cells; Goals; Guanine Nucleotide Exchange Factors; Immunofluorescence Microscopy; Knowledge; Lead; Malignant Neoplasms; Mammalian Cell; Mitotic; Modeling; Molecular; Molecular Biology; Molecular Conformation; Monomeric GTP-Binding Proteins; Mutagenesis; Myosin ATPase; Myosin Type II; Phosphorylation; Phosphotransferases; Positioning Attribute; Proteins; Recruitment Activity; Regulation; Research; Role; Signal Transduction; Site; Testing; Therapeutic; Time; Work; aurora B kinase; cell transformation; cell type; human PLK1 protein; male; novel; time use

DESCRIPTION (provided by applicant): Our long-term goal is to understand the molecular mechanism(s) that regulate(s) cytokinesis in mammalian cells, and to use this knowledge to develop novel cancer therapeutic strategies. Dysfunctional regulation of cytokinesis can lead to uncontrolled cell proliferation, a key characteristic of cancer. The integrity of cytokinesis relies on the precise coordinated regulation of the positioning and timing of contractile ring assembly. One of the prevalent models is that signals from the central spindle determine the positioning and timing of contractile ring assembly. Polo-like kinase 1 (Plk1) and aurora kinase B (aurora B) are two important mitotic kinases, which localize to the central spindle and coordinate with small GTPase signaling to regulate contractile ring assembly. The small GTPase proteins, such as RhoA, Rac1, and Cdc42, are activated by guanine nucleotide exchange factors (GEFs) and inactivated by GTPase-activating proteins (GAPs). Thus far, at least three GEFs, i.e. ECT2, GEF-H1, and MyoGEF, are implicated in regulating cytokinesis. However, it is still not clear why cells need three GEFs for cytokinesis and how they cooperate to regulate equatorial RhoA activation and localization. The overall objective of this grant application is to understand how MyoGEF regulates cytokinesis and why mammalian cells need more than one GEF for cytokinesis. Our central hypothesis is that Plk1 and aurora B coordinate to recruit MyoGEF to the central spindle and cleavage furrow, where MyoGEF cooperates with ECT2 and/or GEF-H1 to regulate RhoA activation and localization at the cleavage furrow. We propose two aims to test our central hypothesis, by using a combination of biochemistry, cell biology, and molecular biology, with mammalian cells as a model. In Specific Aim #1, we will elucidate how Plk1 and aurora B coordinate with MyoGEF in regulating cytokinesis. This aim will test our working hypothesis that, during anaphase, aurora B creates a Plk1 docking site in MyoGEF and allows Plk1 to bind and phosphorylate MyoGEF, in turn promoting the recruitments of MyoGEF to the central spindle, thus contributing to the regulation of equatorial RhoA activation and myosin contractile ring assembly. In Specific Aim #2, we will determine why mammalian cells need more than one GEF for cytokinesis. This aim will test our working hypothesis: 1) MyoGEF, ECT2, and/or GEF-H1 redundantly regulate cytokinesis in certain cells; 2) MyoGEF, ECT2, and/or GEF-H1 are implicated in cell type-specific regulation of cytokinesis; 3) MyoGEF, ECT2, and GEF-H1 coordinate the regulation of equatorial RhoA activation and localization. PUBLIC HEALTH RELEVANCE: The research outlined in this proposal is aimed at understanding the molecular mechanisms for the regulation of cytokinesis. Dysfunctional regulation of cytokinesis can lead to uncontrolled cell proliferation, a key characteristic of cancer.

描述(申请人提供)：我们的长期目标是了解调控(S)哺乳动物细胞胞质分裂的分子机制(S)，并利用这一知识开发新的癌症治疗策略。胞质分裂的功能失调会导致细胞增殖失控，这是癌症的一个关键特征。胞质分裂的完整性依赖于收缩环组件的位置和时机的精确协调调节。一种流行的模型是，来自中心主轴的信号决定了收缩环组件的位置和时机。Polo-like kinase1(Plk1)和aurora kinaseB(Aurora B)是两种重要的有丝分裂酶，它们定位于中央纺锤体，并与小的GTP酶信号协同调节收缩环的组装。小分子GTP酶蛋白，如RhoA、rac1和CDC42，被鸟嘌呤核苷酸交换因子(GEF)激活，被GTP酶激活蛋白(GAP)灭活。到目前为止，至少有三个GEF参与了胞质分裂的调控，即ECT2、Global-H1和Myogef。然而，目前还不清楚为什么细胞需要三个GEF来进行胞质分裂，以及它们如何协同调节赤道RhoA的激活和定位。这项赠款申请的总体目标是了解Myogef是如何调节胞质分裂的，以及为什么哺乳动物细胞需要不止一个全环基金来进行胞质分裂。我们的中心假设是Plk1和Auora B协同将MyoGlobal招募到中央纺锤体和卵裂沟，在那里MyoGlobal与ECT2和/或Global-H1合作调节RhoA的激活和在卵裂沟的定位。我们提出了两个目的来检验我们的中心假设，通过使用生物化学、细胞生物学和分子生物学的组合，以哺乳动物细胞为模型。在特定的目标#1中，我们将阐明Plk1和Auora B如何与Myogef协调调节细胞质分裂。这一目的将检验我们的工作假说，即在后期，极光B在MyoGlobal中创建一个Plk1停靠位点，并允许Plk1结合并磷酸化MyoGlobal，进而促进MyoGlobal向中央纺锤体的招募，从而有助于调节赤道RhoA激活和肌球蛋白收缩环组装。在特定的目标#2中，我们将确定为什么哺乳动物细胞需要不止一种全球环境基金来进行胞质分裂。这一目标将检验我们的工作假说：1)MyoGlobal、ECT2和/或全环基金-H1冗余地调节某些细胞的胞质分裂；2)MyoGlobal、ECT2和/或全环基金-H1参与对细胞质分裂的特定类型的调节；3)Myo全环基金、ECT2和全环基金-H1协调赤道RhoA激活和定位的调节。 公共卫生相关性：本提案中概述的研究旨在了解胞质分裂调节的分子机制。胞质分裂的功能失调会导致细胞增殖失控，这是癌症的一个关键特征。