The role of the NIMA kinase in mitotic regulation

描述(由申请人提供)：对有丝分裂的错误调节导致癌症和出生缺陷的进展，关于有丝分裂调节的发现对医学研究和疾病治疗产生了积极的影响。然而，新的见解和对医学的进一步影响的潜力显然是存在的。例如，最戏剧性但最不被了解的有丝分裂过程之一是核孔复合体(NPC)的分解和重新组装，这些巨大的结构提供了跨越核膜的受调控的门户。这一过程如何被调控并与其他有丝分裂事件整合可能涉及可逆的磷酸化，我们计划的实验将有助于验证这一假设。我们已经证明尼杜拉曲霉的NIMA有丝分裂激酶通过促进NPC的分解来启动有丝分裂。NIMA既是促进鼻咽癌分解所必需的，也是足够的，并显着影响脊椎动物细胞的有丝分裂，表明存在保守的有丝分裂底物。因此，核假单胞菌提供了一个强大和复杂的模型系统，在其中了解鼻咽癌细胞的有丝分裂调控。这一应用的目的包括利用亲和纯化和质谱学来确定鼻咽癌相互作用组中有丝分裂的动态变化，以确定新的鼻咽癌蛋白(NUP)以及参与有丝分裂调控的NUP相关蛋白。此外，我们还将重点研究一种新的Nup相关蛋白(AN0162)，它包含一个跨膜结构域，可能编码第四个跨膜Nup。我们的数据表明，AN0162具有有丝分裂功能，在有丝分裂过程中维持核仁周围核膜上的外周mRNA输出因子Gle1，我们将检验这一假说。我们的第三个重点是Nup2及其相关蛋白NupA、Importin 1和Importin 2的有丝分裂功能。在有丝分裂过程中，Nup2和NupA从NPC转移到染色质，同时它们也被磷酸化。我们将检验这一假设，即NupA介导Nup2的有丝分裂染色质位置，进而控制Importin 1和2的功能，以调节有丝分裂进程。由于磷酸化似乎是这一过程中不可或缺的一部分，最终目标是定位Nup2、NupA和Importin 2内的有丝分裂磷酸化位点，然后对特定的磷酸化位点进行体内突变分析，以确定它们的功能。

DESCRIPTION (provided by applicant): Incorrect regulation of mitosis contributes to progression of cancer and birth defects and discoveries regarding the regulation of mitosis have positively impacted medical research and disease treatments. However, the potential for new insights and further impact on medicine clearly exists. For example, one of the most dramatic yet least understood mitotic processes is the disassembly and reassembly of nuclear pore complexes (NPCs), massive structures providing regulated gateways across the nuclear envelope. How this process is regulated and integrated with other mitotic events potentially involves reversible phosphorylation and our planned experiments will help test this hypothesis. We have shown the NIMA mitotic kinase of Aspergillus nidulans initiates mitosis by promoting NPC disassembly. NIMA is both required and sufficient to promote NPC disassembly and markedly affects mitosis in vertebrate cells suggesting the existence of conserved mitotic substrates. A. nidulans therefore provides a powerful and sophisticated model system in which to understand mitotic regulation of NPCs. The aims of this application include defining the dynamic mitotic changes in the NPC interactome using affinity purifications and mass spectrometry to identify new NPC proteins (Nups) as well as Nup associated proteins involved in mitotic regulation. In addition we will also focus studies on a new Nup associated protein (AN0162) which contains a transmembrane domain and potentially encodes a fourth transmembrane Nup. Our data suggest that AN0162 has a mitotic function to maintain the peripheral mRNA export factor Gle1 on the nuclear envelope surrounding the nucleolus during mitosis and we will test this hypothesis. Our third focus is on the mitotic functions of Nup2 and its associated proteins NupA, importin 1 and importin 2. Nup2 and NupA translocate from NPCs to chromatin during mitosis when they also become phosphorylated. We will test the hypothesis that NupA mediates the mitotic chromatin location of Nup2, which in turn controls the functions of importin 1 and 2 to regulate mitotic progression. As phosphorylation appears integral to this process, the final aim is to map mitotic phosphorylation sites within Nup2, NupA and importin 2 and then carry out in vivo mutational analysis of the specific phosphorylation sites to determine their function.