Molecular steps in TAO kinase regulation

TAO 激酶调节的分子步骤

基本信息

批准号：
10473664
负责人：
MELANIE H. COBB
金额：
$ 32.8万
依托单位：
UT SOUTHWESTERN MEDICAL CENTER
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-09-01 至 2023-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10473664
关键词：
Binding Binding Sites Biochemical Biochemical Process Biological Biological Assay Bypass Catalytic Domain Cell Nucleus Cells Chemicals Complex Crystallization Cytoplasm Disinhibition Dissociation Drug Targeting Elements Enzymes Event Exhibits Foundations Future In Vitro Knowledge Literature MAP Kinase Gene MAP Kinase Kinase Kinase Membrane Modeling Molecular Nature Pathologic Pathway interactions Phosphoric Monoester Hydrolases Phosphorylation Phosphotransferases Physiological Processes Positioning Attribute Protein Kinase Protein phosphatase Proteins RNA Processing Recombinants Regulation Reporting Schistosoma Serine Signal Transduction Specificity Structure Surface Therapeutic Virus Diseases Work base drug development drug discovery experience in vivo influenza infection inhibitor insight kinase inhibitor novel novel therapeutics p38 Mitogen Activated Protein Kinase protein complex reconstitution viral RNA

项目摘要

Despite their discovery over 20 years ago, TAO protein kinases (TAO1-3) remain understudied. In particular, we lack an understanding of the mechanisms regulating TAO activation, how they recognize substrates, and how these kinases contribute to key physiological processes. We originally identified TAOs through a large- scale effort to find membrane proximal components of MAPK cascades and showed that TAOs are MAP3Ks in the p38 pathway. Recent work now reveals that TAOs are essential for schistosome and viral infections and viral RNA processing and export from the nucleus. These findings suggest that TAOs are drug targets for a range of pathophysiological conditions and beg for a greater understanding of how their activities are controlled. Here, we propose to develop a paradigm for the biochemical regulation of TAO protein kinases through their integration with phosphoprotein phosphatase 1 (PP1). These results should advance future drug discovery efforts to provide new therapeutic entry points for treating a range of diverse pathological conditions. An obstacle in realizing their therapeutic potential is the limited knowledge of their regulation and partners. In searching for regulatory interactions, we found that TAOs directly bind PP1 and its R7 regulatory subunit. While PP1 dephosphorylates half the proteins in the cell, its activity is largely restricted within heteromeric complexes by regulatory subunits. Recent literature indicates that R7 maintains PP1 in an inactive state. We propose that TAOs modulate PP1 phosphatase activity via direct interactions and by R7 phosphorylation. The connection with PP1 offers TAOs wide opportunities to impact cellular control mechanisms. Our specific aims are to 1) determine how the TAO-PP1 complex regulates TAO activity; and 2) determine how TAO through R7 regulates PP1 activity. Biochemical and cell biological studies will take advantage of a model of a TAO2-PP1 complex based on our crystal structure of the TAO2 kinase domain that shows the PP1 binding motif on TAO. The relevance of this interaction is supported by our recent work revealing co-localization of TAO2 and PP1 in structures in the nucleus and the cytoplasm. Our extensive experience in identifying and characterizing TAOs, determining the structure of the TAO kinase domain, identifying chemically tractable inhibitors, and elucidating TAO-dependent pathways, since our discovery of these kinases, puts us in a unique position to determine biochemical processes that will provide a foundation for TAO kinases as subjects of drug development.

尽管 TAO 蛋白激酶 (TAO1-3) 已在 20 多年前被发现，但人们对其的研究仍然不足。特别是，我们缺乏对调节 TAO 激活的机制、它们如何识别底物以及这些激酶如何促进关键生理过程的了解。我们最初通过大规模努力寻找 MAPK 级联的膜近端成分来识别 TAO，并表明 TAO 是 p38 途径中的 MAP3K。最近的研究表明，TAO 对于血吸虫和病毒感染以及病毒 RNA 加工和从细胞核输出至关重要。这些发现表明，TAO 是一系列病理生理状况的药物靶标，需要更好地了解它们的活性是如何控制的。在这里，我们建议通过 TAO 蛋白激酶与磷蛋白磷酸酶 1 (PP1) 的整合来开发 TAO 蛋白激酶生化调节的范例。这些结果将推动未来的药物发现工作，为治疗一系列不同的病理状况提供新的治疗切入点。实现其治疗潜力的一个障碍是对其监管和合作伙伴的了解有限。在寻找调控相互作用时，我们发现 TAO 直接结合 PP1 及其 R7 调控亚基。虽然 PP1 使细胞中一半的蛋白质去磷酸化，但其活性在很大程度上受到调节亚基的异聚复合物的限制。最近的文献表明，R7 使 PP1 保持在非活性状态。我们认为 TAO 通过直接相互作用和 R7 磷酸化来调节 PP1 磷酸酶活性。与 PP1 的连接为 TAO 提供了影响细胞控制机制的广泛机会。我们的具体目标是 1) 确定 TAO-PP1 复合物如何调节 TAO 活性； 2) 确定 TAO 如何通过 R7 调节 PP1 活性。生化和细胞生物学研究将利用基于我们的 TAO2 激酶结构域晶体结构的 TAO2-PP1 复合物模型，该结构显示了 TAO 上的 PP1 结合基序。我们最近的工作揭示了 TAO2 和 PP1 在细胞核和细胞质结构中的共定位，支持了这种相互作用的相关性。自从我们发现这些激酶以来，我们在识别和表征 TAO、确定 TAO 激酶结构域的结构、识别化学上可处理的抑制剂以及阐明 TAO 依赖性途径方面拥有丰富的经验，这使我们在确定生化过程方面处于独特的地位，这些过程将提供为 TAO 激酶作为药物开发主题奠定了基础。