THE NIMA PROTEIN KINASE IN MITOTIC REGULATION

有丝分裂调节中的 NIMA 蛋白激酶

• 批准号: 6320385
• 负责人: STEPHEN A OSMANI
• 金额: $ 10.75万
• 依托单位: GEISINGER CLINIC
• 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 2001-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6320385
• 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以惊人的速度加速。这些新的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蛋白激酶在调节Nidulans细胞周期中起着关键作用。越来越多的数据表明，NIMA相关的激酶也调节着人类的细胞周期。这项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。对NIMA在细胞程序性死亡中的作用进行了分析，并验证了NIMA通过促进DNA缩合而在细胞程序性死亡中发挥作用的假说。组蛋白H3的磷酸化对有丝分裂时DNA缩合是必不可少的这一假说将在多核拟青霉中得到验证。我们还将测试这一假设，即NIMA是在有丝分裂时使组蛋白H3磷酸化的激酶。如果NIMA不是H3激酶，则该激酶将被分离，并由NIMA研究其调节，因为有丝分裂的H3磷酸化依赖于NIMA并由NIMA促进。NIMA通过相互作用或控制凝聚素来促进DNA缩合的假设也有待验证。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机制，可以防止过早的有丝分裂。然而，确实存在其他水平的检查点控制有丝分裂的启动，因为nidulans不能酪氨酸磷酸化MPF的菌株在细胞周期中正常进行，如果DNA复制停止，也会阻止有丝分裂的启动。为了分离额外的调节功能，我们设计了基因筛选，以分离新的有丝分裂调节因子，这些调节因子不能通过MPF的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。概述了定义NIMA在固定细胞和活细胞中的定位以及NIMA中负责其细胞周期特异性定位和降解的结构域的实验。最后，将测试核NIMA促进MPF移位到核的能力。