Molecular steps in TAO kinase regulation

TAO 激酶调节的分子步骤

• 批准号: 10185032
• 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
• 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/10185032
• 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/antagonist; insight; kinase inhibitor; novel; novel therapeutics; p38 Mitogen Activated Protein Kinase; protein complex; reconstitution; viral RNA

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（TAO 1 -3）在20多年前被发现，但其研究仍然不足。特别是，我们缺乏对调节TAO激活的机制的理解，它们如何识别底物，以及这些激酶如何促进关键的生理过程。我们最初通过大规模努力发现MAPK级联的膜近端组分来鉴定TAO，并显示TAO是p38途径中的MAP 3 K。最近的研究表明，TAO对于核糖体和病毒感染以及病毒RNA加工和从细胞核输出是必不可少的。这些发现表明TAO是一系列病理生理条件的药物靶点，并要求更好地了解其活性是如何控制的。在这里，我们建议开发一种模式，通过其整合与磷蛋白磷酸酶1（PP 1）的TAO蛋白激酶的生化调节。这些结果应该推动未来的药物发现工作，为治疗一系列不同的病理条件提供新的治疗切入点。实现其治疗潜力的一个障碍是对它们的调节和伙伴的了解有限。在寻找调节相互作用时，我们发现TAO直接结合PP 1及其R7调节亚基。 虽然PP 1使细胞中一半的蛋白质去磷酸化，但其活性在很大程度上被调节亚基限制在异聚复合物内。最近的文献表明，R7保持PP 1处于非活性状态。我们认为TAO通过直接相互作用和R7磷酸化调节PP 1磷酸酶活性。与PP 1的连接为TAO影响细胞控制机制提供了广泛的机会。我们的具体目标是1）确定TAO-PP 1复合物如何调节TAO活性; 2）确定TAO通过R7如何调节PP 1活性。生物化学和细胞生物学研究将利用基于我们的TAO 2激酶结构域的TAO 2-PP 1复合物模型，该结构域显示了TAO上的PP 1结合基序。我们最近的工作揭示了TAO 2和PP 1在细胞核和细胞质结构中的共定位，这支持了这种相互作用的相关性。我们在鉴定和表征TAO、确定TAO激酶结构域的结构、鉴定化学上易处理的抑制剂和阐明TAO依赖性途径方面的丰富经验，自我们发现这些激酶以来，使我们处于独特的位置，以确定将为TAO激酶作为药物开发主体提供基础的生化过程。