Checkpoint control of cytokinesis

描述（由申请人提供）：胞质分裂，即一个细胞物理分裂为两个子细胞，是细胞生殖周期的最后阶段，也是人们了解最少的阶段。正确地定时胞质分裂的过程，使其仅在染色体复制和分离后发生，是防止灾难性的基因组不稳定性所必需的，因此，胞质分裂与细胞周期的其他事件一起严格调节。我们已经取得了显着的进展，在确定和表征蛋白质的胞质分裂所必需的胞质分裂研究的领先模式生物，裂殖酵母粟酒裂殖酵母。我们现在建议更好地了解这些无数的蛋白质是如何控制的。海马相关的蛋白激酶级联称为分隔起始网络（SIN）控制的装配，维护和收缩的肌动球蛋白收缩环，因此是直接上游调节胞质分裂在S。粟酒然而，我们的知识是有限的，以最终确保协调SIN活动，从而胞质分裂，与其他事件的有丝分裂。在其他机制中，SIN功能被泛素连接酶Dma 1直接抑制，这包括有丝分裂检查点信号传导的第二分支。鉴于我们的新认识，即Dma1是有丝分裂起始时polo样激酶Plo 1的一般抑制剂， 我们将研究这种控制有丝分裂抑制的机制是否与人类肿瘤抑制因子CHFR相同。我们将确定Dma 1活性和定位如何通过上游途径（包括CK 1）在整个细胞周期中控制。我们提出了一套全面的生物化学和细胞生物学实验，以填补这些知识空白。这些集中的机制研究将与磷酸蛋白质组学和遗传筛选相补充，旨在更好地了解有丝分裂期间的信号转导景观。虽然信号网络的一些布线方面可能会发现生物体之间的变化，这些研究将有重大影响，了解胞质分裂如何在原则上可以夹带有丝分裂的其他事件，以保护基因组的完整性。

DESCRIPTION (provided by applicant): Cytokinesis, the physical division of one cell into two daughter cells, is the final stage of the cell reproductive cycle and the least well understood. Correctly timing the process of cytokinesis so that it occurs only after chromosome replication and segregation is necessary to prevent catastrophic genomic instability and accordingly, cytokinesis is strictly regulated in concert with other events of the cell cycle. We have made significant progress in identifying and characterizing proteins essential for cytokinesis using a leading model organism for cytokinesis studies, the fission yeast Schizosaccharomyces pombe. We now propose to gain a better understanding of how these myriad proteins are controlled. A Hippo-related protein kinase cascade termed the septation initiation network (SIN) controls assembly, maintenance, and constriction of the actomyosin contractile ring and is therefore the immediate upstream regulator of cytokinesis in S. pombe. Our knowledge is limited however as to what ultimately ensures the coordination of SIN activity and thus cytokinesis, with other events of mitosis. Among other mechanisms, SIN function is directly inhibited by the ubiquitin ligase Dma1 and this comprises a second branch of mitotic checkpoint signaling. Given our new understanding that Dma1 is a general inhibitor of the polo-like kinase, Plo1 at mitotic initiation, we will study whether this mechanism of controlling mitotic inhibition is shared with the human tumor suppressor CHFR. We will determine how Dma1 activity and localization are controlled throughout the cell cycle by upstream pathways including one comprising CK1. We propose a comprehensive set of biochemical and cell biological experiments to fill these knowledge gaps. These focused mechanistic studies will be complemented with phosphoproteomic and genetic screens designed to better understand the signaling landscape during mitosis. Although some wiring aspects of the signaling networks may be found to vary between organisms, these studies will have a major impact for understanding how cytokinesis can in principle be entrained with other events of mitosis to protect genome integrity.