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.

我们对细胞周期调节的理解以惊人的速度加速了。 这些新见解对我们对癌症的理解和治疗产生了重大影响。 这种影响可能会随着对细胞周期控制的进一步了解而增加。 NIMA蛋白激酶在调节曲霉菌中的细胞周期中起关键作用。 增加数据表明，NIMA相关的激酶也调节人类的细胞周期。 该赠款概述了旨在进一步了解细胞周期控制的实验。 将要分析与NIMA相互作用并导致细胞周期停滞的新高度保守的蛋白质。 NIMA在程序性细胞死亡中的作用应进行分析，并测试了NIMA通过促进DNA凝结在程序性细胞死亡中起作用的假设。 组蛋白H3的磷酸化对于有丝分裂时的DNA缩合至关重要的假设应在曲霉中进行测试。 我们还将检验以下假设：NIMA是在有丝分裂时磷酸化组蛋白H3的激酶。 如果NIMA不是H3激酶，则该激酶将被分离出来，并由NIMA进行调节，因为有丝分裂H3磷酸化取决于NIMA，并由NIMA促进。 NIMA通过相互作用或控制冷凝蛋白促进DNA凝结的假设也可以进行测试。 先前的工作表明，MPF的酪氨酸磷酸化是防止过度有丝分裂的高度保守机制。 但是，确实存在其他对有丝分裂起始的检查点控制点的控制点，因为无法抑制磷酸化的MPF的Nidulans菌株正常在细胞周期中进展，并且如果停止DNA复制，也会阻止有丝分裂起始。 为了隔离其他调节功能，我们计划的遗传筛选将分离出新的有丝分裂调节剂，这些调节因素不通过MPF的酪氨酸磷酸化而起作用，但可能会调节NIMA。 初步研究表明，在有丝分裂期间，NIMA首先定位于DNA，然后将纺锤体和纺锤体物体定位于纺锤体。概述了实验，以定义NIMA在固定和活细胞中的定位，并定义NIMA内部负责其细胞周期特定定位和降解的域。 最后，将测试核NIMA促进MPF转移到核的能力。