Dissecting the role of Aurora A kinase in patterning the cell cortex during cytokinesis.

项目总结/摘要 胞质分裂是有丝分裂的最后一步，它促进了一个细胞分裂成两个细胞 子细胞动物细胞通过皮层肌动球蛋白的收缩实现胞质分裂 在分离染色体之间的细胞赤道周围形成的收缩环。失败 胞质分裂可导致四倍体细胞的形成， 在肿瘤发生中。为了确保遗传物质的平等分配，收缩环组装是 由后期纺锤体控制。后期纺锤体发出两个叠加的信号， 图案覆盖皮层的收缩性;来自中央纺锤体的信号， 分离染色体促进赤道皮层的收缩性，而来自赤道皮层的信号 中心体微管星状体抑制非赤道皮质的收缩性。最近的工作 C.在我的赞助实验室里，有丝分裂激酶Aurora A在抑制 收缩环蛋白在非赤道皮质上的积累。然而，这一功能是否 Aurora A的基因在人类细胞中是保守的，并且介导细胞凋亡的Aurora A靶位点的身份是确定的。 皮质收缩性抑制目前是未知的。在拟议的工作中，我将确定 Aurora A在形成皮质收缩性中的作用是否在人类细胞中是保守的， 分子置换技术在C. elegans来鉴定Aurora A介导的靶点 抑制皮质收缩性，并确定如何极光A抑制收缩性 与中央纺锤体促进收缩性整合以形成模式收缩环。在目标1中，我 将开发一种检测方法，以监测非赤道皮层的收缩抑制， 在人类细胞中的胞质分裂，并使用它来确定极光A是否在这一过程中具有保守的作用， Aurora A异位靶向质膜是否可以抑制收缩性。在Aim 2A中， 我将利用C的优势。elegans胚胎提供分子替代实验 对胞质分裂调节因子进行无偏筛选，以鉴定调节细胞分裂的Aurora A靶位点， 中心体星状体抑制皮质收缩的能力，并将测试已鉴定的调节位点 保存在人体细胞中。在目标2B中，我将确定极光A和中央纺锤体是如何衍生的。 信号被集成以允许收缩环位置和尺寸的精确规格。 总的来说，这项工作将提供关键的洞察极光A如何有助于图案化皮层 分裂细胞的收缩性。作为靶向Aurora A的抑制剂， 化疗药物，了解Aurora A在调节收缩性中的作用如何与 它在肿瘤发生中的功能有可能影响癌症的治疗策略。

PROJECT SUMMARY/ABSTRACT Cytokinesis is the final step in mitosis and facilitates the physical cleavage of one cell into two daughter cells. Animal cells achieve cytokinesis through the constriction of a cortical actomyosin contractile ring that forms around the cell equator between the segregating chromosomes. Failure of cytokinesis can lead to the formation of tetraploid cells that are thought to be an important intermediate in tumorigenesis. To ensure equal partitioning of the genetic material, contractile ring assembly is controlled by the anaphase spindle. The anaphase spindle sends two superimposed signals that pattern the contractility of the overlying cortex; a signal from the central spindle that forms between the separating chromosomes promotes contractility of the equatorial cortex, and a signal from the centrosomal microtubule asters suppresses contractility of the non-equatorial cortex. Recent work in C. elegans in my sponsor lab has implicated the mitotic kinase Aurora A in suppressing the accumulation of contractile ring proteins on the non-equatorial cortex. However, whether this function of Aurora A is conserved in human cells and the identity of the Aurora A target sites that mediate suppression of cortical contractility are currently unknown. In the proposed work, I will determine whether the role of Aurora A in patterning cortical contractility is conserved in human cells, use molecular replacement techniques in C. elegans to identify the targets of Aurora A-mediated suppression of cortical contractility, and determine how Aurora A suppression of contractility is integrated with central spindle promotion of contractility to pattern contractile ring formation. In Aim1, I will develop an assay to monitor the suppression of contractility on the non-equatorial cortex during cytokinesis in human cells and use it to determine if Aurora A has a conserved role in this process and whether ectopic targeting of Aurora A to the plasma membrane can suppress contractility. In Aim 2A, I will capitalize on the advantages the C. elegans embryo offers for molecular replacement experiments to perform an unbiased screen of cytokinesis regulators to identify the Aurora A target sites that mediate the ability of centrosomal asters to suppress cortical contractility and will test identified regulatory sites in human cells for conservation. In Aim 2B I will determine how Aurora A and central spindle-derived signals are integrated to allow for the precise specification of contractile ring location and dimensions. Collectively, this work will provide crucial insight into how Aurora A contributes to patterning cortical contractility in dividing cells. As inhibitors targeting Aurora A are currently in clinical trials as potential chemotherapeutic agents, understanding how the role of Aurora A in regulating contractility is related to its functions in tumorigenesis has the potential to impact therapeutic strategies in cancer.