Characterization of the Mitotic Exit Network

真核细胞必须在时间上协调各种细胞过程，以确保细胞的保真度 扩散。细胞周期过程的执行或时间协调方面的缺陷会增加基因 不稳定和促进癌症。因此，解决细胞周期保守的机制是非常重要的 规章制度。酿酒酵母有丝分裂出口网络(MEN)是协调几个 有丝分裂退出过程中的细胞周期过程，包括细胞周期蛋白依赖性激酶(CDK)失活、胞质分裂、 有丝分裂纺锤体的拆解和G1基因表达的激活。Mob1-Dbf2激酶复合体是一个关键 是男性的组成部分，与人类Mob1A-Lats激酶复合体同源，其功能是 哺乳动物肿瘤抑制因子。酵母Mob1-Dbf2与胞质分裂、CDC14的激活有关 磷酸酶(通过使CDK磷酸化失活而使有丝分裂退出)和有丝分裂纺锤体功能 通过对极光激酶的调节。然而，酵母菌和酵母菌的作用机理和底物 哺乳动物的Mob1-Dbf2激酶是未知的。拟议工作的目标是确定如何 Mob1-Dbf2激酶复合体与有丝分裂出口和染色体在时间上协调胞质分裂 种族隔离。我们提出了三个目标。第一个目的是确定Mob1-Dbf2在胞质分裂中的作用。我们 将进行细胞生物学、生物化学和遗传学方法来测试男性控制的假设 通过调节靶向膜沉积和激活RAM的胞质分裂(调节ACE2 转录因子和极化形态发生)信号网络，控制细胞质分裂，基因 表达等功能。第二个目的是确定Mob1-Dbf2激酶复合体的作用 在有丝分裂退出和胞质分裂期间，CDC14磷酸酶被激活。我们将检验假设Mob1- Dbf2激酶直接诱导cdc14磷酸酶从核仁释放，并将定义上位性 Mob1-Dbf2和CDCLP与胞质分裂的关系。第三个目标是确定 有丝分裂检查点信号中的Mob1-Dbf2。我们将测试以下假设：Mob1-Dbf2是 依赖于极光的检查点信令。鉴于Mob1-Dbf2的保护，拟议的工作将有所帮助 解决所有与男性相关的信号网络的功能，包括人类hMob1A-LATS1肿瘤 抑制途径，并将有助于阐明癌症发展的潜在机制。

Eukaryotic cells must temporally coordinate diverse cellular processes to ensure the fidelity of cell proliferation. Defects in the execution or temporal coordination of cell cycle processes increase genetic instability and promote cancer. Thus, it is important to resolve the mechanisms of conserved cell cycle regulations. The Saccharomyces cerevisiae Mitotic Exit Network (MEN) is essential for coordinating several cell cycle processes during mitotic exit, including cyclin dependent kinase (CDK) inactivation, cytokinesis, mitotic spindle disassembly and activation of G1 gene expression. The Mob1-Dbf2 kinase complex is a key component of MEN and is orthologous to the human Mob1A-LATS kinase complex, which functions as mammalian tumor suppressor. Yeast Mob1-Dbf2 has been implicated in cytokinesis, activation of Cdc14 phosphatase (which enables mitotic exit by inactivating CDK phosphorylations) and mitotic spindle function via regulation of Aurora kinase. Nevertheless, the functional mechanisms and substrates of yeast and mammalian Mob1-Dbf2 kinases are not known. The goal of the proposed work is to determine how the Mob1-Dbf2 kinase complex temporally coordinates cytokinesis with mitotic exit and chromosome segregation. We propose three aims. The first aim is to determine the role of Mob1-Dbf2 in cytokinesis. We will conduct cell biological, biochemical and genetic approaches to test the hypothesis that MEN controls cytokinesis by regulating targeted membrane deposition and by activating the RAM (Regulation of Ace2 transcription factor and polarized Morphogenesis) signaling network, which controls cytokinesis, gene expression and other functions. The second aim is to determine the role of the Mob1-Dbf2 kinase complex in Cdc14 phosphatase activation during mitotic exit and cytokinesis. We will test the hypothesis that Mob1- Dbf2 kinase directly induces Cdc14 phosphatase release from the nucleolus and will define the epistatic relationship of Mob1-Dbf2 and Cdclp with respect to cytokinesis. The third aim is to determine the role of Mob1-Dbf2 in mitotic checkpoint signaling. We will test the hypothesis that Mob1-Dbf2 is required for Aurora-dependent checkpoint signaling. Given the conservation of Mob1-Dbf2, the proposed work will help resolve the function of all MEN-related signaling networks, including the human hMob1A-LATS1 tumor suppressor pathway, and will help elucidate the underlying mechanisms of cancer development.