Mob1 Localization and Function During Mitosis

Mob1 在有丝分裂期间的定位和功能

• 批准号: 8292148
• 负责人: Charles Bradley Shuster
• 金额: $ 24.22万
• 依托单位: NEW MEXICO STATE UNIVERSITY LAS CRUCES
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-01 至 2014-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8292148
• 关键词: Actins; Adult; Affect; Anaphase; Aneuploidy; Animals; Architecture; Binding Proteins; Biochemical; Cell Cycle; Cell Cycle Arrest; Cell Cycle Checkpoint; Cell Cycle Proteins; Cell Cycle Regulation; Cell Proliferation; Cell division; Cells; Centromere; Chromosome Segregation; Complex; Cytokinesis; Data; Dependence; Development; Drosophila genus; Elements; Ensure; Eukaryota; Event; Family; Fission Yeast; Foundations; Frequencies; G1/S Transition; Gene Duplication; Gene Family; Genes; Genome; Growth; Homologous Gene; Human; Image; Interphase; Kinetochores; Life; Maintenance; Malignant Neoplasms; Mammalian Cell; Mammals; Mediator of activation protein; Mitosis; Mitotic; Mitotic spindle; Molecular; Molecular Weight; Organ Size; Orthologous Gene; Pathway interactions; Pattern; Phosphorylation; Phosphotransferases; Play; Ploidies; Process; Protein Family; Protein Isoforms; Proteins; RNA Interference; Reporting; Role; Saccharomyces cerevisiae; Saccharomycetales; Signal Transduction; Sister Chromatid; Small Interfering RNA; Testing; Tetraploidy; Tissues; Tumor Suppressor Proteins; Yeasts; aurora B kinase; base; constriction; genetic analysis; insight; loss of function; men; mutant; novel; nuclear division; response; spindle pole body; tumor; tumorigenesis

Maintenance of chromosomal ploidy during cell division requires a precise coordination of chromosome segregation and cytokinesis such that the contractile ring does not assemble before all replicated sister chromatids are correctly attached to the mitotic spindle and the spindle assembly checkpoint is satisfied. In budding and fission yeast, this process is facilitated by a signaling cascade termed the Mitotic Exit Network/Septation Initiation Network that coordinates mitotic exit and cytokinesis, is based at the spindle pole bodies, and plays an active role in initiating constriction of the actin ring. To date, few functional homologues have been characterized in animal cells, but in the case of the terminal components (Mob1 and Dbf2/Sid2), there have been expansions in both gene families. And while tumor suppressor functions have been ascribed to the mammalian and Drosophila orthologs of Mob1 and Dbf2/Sid2 during G1/S, little is known about how these molecules participate in mitosis and cytokinesis in animal cells. Preliminary studies of Mob1 isoforms in cultured human cells indicate that the localization dynamics mirror that observed in yeast, with Mob1 enriched at the kinetochores and spindle poles early in mitosis, and the spindle midzone and midbody during cytokinesis. Moreover, we have determined that Mob1 and the chromosomal passenger complex are mutually dependent on each other kinetochore localization early in mitosis. Lastly, we identified Large Tumor Supressor 2 (Lats2) as a Mob1A-specific binding protein and possible functional homolog of the Dbf2/Sid2 kinase. Using these preliminary studies as a foundation, this application seeks to combine molecular, biochemical and live cell analyses to test the hypothesis that Mob1 proteins perform roles in regulating in maintaining chromosomal ploidy during both mitosis and interphase. The lines of experimentation that form the Specific Aims will: 1) Determine the molecular determinants of Mob1 localization to the kinetochore; 2) Dissect how Mob1 affects Aurora B function at the kinetochore; and 3) Assess the involvement of Mob1 in the Lats2-p53 response to cytoskeletal disruption. These studies will shed novel insights into a gene family that in animal cells appears to act as a negative regulator of cell proliferation (and whose loss of function is associated with tumor formation), yet is essential for completing cell division in yeast. It is anticipated that these studies will help us reconcile how Mob1 is capable of participating in both of these very different but absolutely critical features of cell cycle regulation.

细胞分裂过程中染色体倍性的维持需要染色体的精确协调 分离和胞质分裂，使得收缩环不会在所有复制的姐妹之前组装 染色单体正确附着在有丝分裂纺锤体上，并且纺锤体组装检查点得到满足。在 对于出芽和裂殖酵母来说，这个过程是由称为有丝分裂出口的信号级联促进的 网络/分隔起始网络，协调有丝分裂退出和胞质分裂，基于纺锤体极 体，并在启动肌动蛋白环收缩中发挥积极作用。迄今为止，很少有功能同系物 已在动物细胞中进行了表征，但就末端成分（Mob1 和 Dbf2/Sid2）而言， 两个基因家族都有扩展。虽然肿瘤抑制功能被归因于 Mob1 和 Dbf2/Sid2 在 G1/S 期间的哺乳动物和果蝇直系同源物，但我们对它们如何发挥作用知之甚少。 分子参与动物细胞的有丝分裂和胞质分裂。培养物中Mob1亚型的初步研究 人类细胞表明，定位动力学与在酵母中观察到的情况相似，Mob1 在 有丝分裂早期的着丝粒和纺锤体极，以及胞质分裂期间的纺锤体中区和中体。 此外，我们确定 Mob1 和染色体乘客复合物相互依赖 在有丝分裂早期彼此着丝粒定位。最后，我们将大肿瘤抑制因子 2 (Lats2) 确定为 Mob1A 特异性结合蛋白和 Dbf2/Sid2 激酶的可能功能同源物。利用这些初步 该应用程序以研究为基础，旨在结合分子、生化和活细胞分析来测试 Mob1 蛋白在维持染色体倍性方面发挥调节作用的假设 有丝分裂和间期。形成具体目标的实验路线将： 1) 确定 Mob1 定位于动粒的分子决定因素； 2）剖析Mob1如何影响Aurora B 在动粒处发挥作用； 3) 评估 Mob1 在 Lats2-p53 反应中的参与 细胞骨架破坏。这些研究将为动物细胞中出现的基因家族提供新的见解 作为细胞增殖的负调节因子（其功能丧失与肿瘤相关） 形成），但对于完成酵母细胞分裂至关重要。预计这些研究将帮助我们 协调 Mob1 如何能够参与这两个截然不同但绝对关键的细胞特征 循环调节。