THE NIMA PROTEIN KINASE IN MITOTIC REGULATION

有丝分裂调节中的 NIMA 蛋白激酶

• 批准号: 6519344
• 负责人: STEPHEN A OSMANI
• 金额: $ 31.71万
• 依托单位: OHIO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-07-01 至 2004-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6519344
• 关键词: DNA replication; apoptosis; cell cycle; cell growth regulation; enzyme activity; enzyme mechanism; laboratory rabbit; phosphorylation; protein kinase; protein localization; protein structure function

Our understanding of cell cycle regulation has accelerated at an amazing pace. These new insights have had a major impact upon our understanding and treatment of cancer. This impact is likely to increase with further understanding of cell cycle control. The NIMA protein kinase plays a pivotal role in regulating the cell cycle in Aspergillus nidulans. Increasing data indicate that NIMA related kinases regulate the cell cycle in humans as well. This grant outlines experiments aimed at furthering our understanding of cell cycle control. New highly conserved proteins that interact with NIMA and cause cell cycle arrest are to be analyzed. The role of NIMA in programmed cell death is to be analyzed and the hypothesis tested that NIMA plays a role in programmed cell death by promoting DNA condensation. The hypothesis that phosphorylation of histone H3 is essential for DNA condensation at mitosis is to be tested in A. nidulans. We will also test the hypothesis that NIMA is the kinase that phosphorylates histone H3 at mitosis. If NIMA is not the H3 kinase then this kinase will be isolated and its regulation by NIMA studied as mitotic H3 phosphorylation is dependent upon NIMA and is promoted by NIMA. The hypothesis that NIMA promotes DNA condensation by interacting or controlling condensin is also to be tested. Previous work has demonstrated that tyrosine phosphorylation of MPF is a highly conserved mechanism to prevent premature mitosis. However, other levels of checkpoint control over mitotic initiation do exist because A. nidulans strains unable to tyrosine phosphorylate MPF progress normally through the cell cycle and also arrest mitotic initiation if DNA replication is stopped. To isolate additional regulatory functions we plan genetic screens that will isolate new regulators of mitosis that do not function through tyrosine phosphorylation of MPF but may regulate NIMA. Preliminary studies indicate that during mitosis NIMA localizes first to the DNA, then the spindle and finally to the spindle pole body. Experiments are outlined to define the localization of NIMA in fixed and live cells and to define domains within NIMA that are responsible for its cell cycle specific localization and degradation. Finally, the ability of nuclear NIMA to promote translocation of MPF to the nucleus will be tested.

我们对细胞周期调控的理解正在以惊人的速度加速。 这些新见解对我们对癌症的理解和治疗产生了重大影响。 随着对细胞周期控制的进一步了解，这种影响可能会增加。 NIMA 蛋白激酶在构巢曲霉细胞周期的调节中发挥着关键作用。 越来越多的数据表明 NIMA 相关激酶也调节人类的细胞周期。 这笔资助概述了旨在加深我们对细胞周期控制的理解的实验。 与 NIMA 相互作用并导致细胞周期停滞的新的高度保守的蛋白质将被分析。 NIMA 在程序性细胞死亡中的作用有待分析，并检验 NIMA 通过促进 DNA 凝聚在程序性细胞死亡中发挥作用的假设。 组蛋白 H3 的磷酸化对于有丝分裂时 DNA 浓缩至关重要的假设将在构巢曲霉中进行测试。 我们还将检验以下假设：NIMA 是有丝分裂时磷酸化组蛋白 H3 的激酶。 如果 NIMA 不是 H3 激酶，则将分离该激酶并研究 NIMA 对其的调节，因为有丝分裂 H3 磷酸化依赖于 NIMA 并由 NIMA 促进。 NIMA 通过相互作用或控制凝缩蛋白促进 DNA 凝缩的假设也有待检验。 先前的工作已经证明MPF的酪氨酸磷酸化是一种高度保守的防止过早有丝分裂的机制。 然而，确实存在对有丝分裂起始的其他水平的检查点控制，因为构巢曲霉菌株无法在细胞周期中正常地使MPF进程酪氨酸磷酸化，并且在DNA复制停止时也阻止有丝分裂起始。 为了分离出额外的调节功能，我们计划进行遗传筛选，分离出新的有丝分裂调节因子，这些调节因子不通过 MPF 酪氨酸磷酸化发挥作用，但可能调节 NIMA。 初步研究表明，在有丝分裂过程中，NIMA 首先定位于 DNA，然后定位于纺锤体，最后定位于纺锤体极体。概述了实验来定义 NIMA 在固定细胞和活细胞中的定位，并定义 NIMA 内负责其细胞周期特异性定位和降解的域。 最后，将测试核NIMA促进MPF转位至细胞核的能力。