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.

尽管他们在20多年前就发现了TAO蛋白激酶(TAO1-3)，但对它的研究仍然很少。特别是，我们缺乏对TAO激活的调节机制，它们如何识别底物，以及这些激酶如何参与关键的生理过程。我们最初通过大规模寻找MAPK级联的膜近端成分发现了Tao，并证明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的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，并要求更多地了解它们的活动是如何控制的。在这里，我们建议开发一个范例，通过它们与磷酸蛋白磷酸酶1(PP1)的整合来对TAO蛋白激酶进行生化调节。这些结果应该会推动未来的药物发现努力，为治疗一系列不同的病理疾病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有限了解。在寻找调节相互作用的过程中，我们发现Taos直接与PP1及其R7调节亚基结合。 虽然PP1使细胞中一半的蛋白质去磷酸化，但它的活性在很大程度上受到调节亚基的限制。最近的文献表明，R7维持PP1处于非活性状态。我们认为，Taos通过直接相互作用和R7磷酸化来调节PP1磷酸酶活性。与PP1的联系为Taos提供了广泛的机会来影响蜂窝控制机制。我们的具体目标是1)确定TAO-PP1复合体如何调节TAO活性；以及2)确定TAO到R7如何调节PP1活性。生化和细胞生物学研究将利用基于我们的TAO2激酶域的晶体结构的TAO2-PP1复合体的模型，该结构显示了TAO上的PP1结合基序。这种相互作用的相关性得到了我们最近的工作的支持，该工作揭示了TAO2和PP1在细胞核和细胞质的结构中共同定位。自从我们发现这些激酶以来，我们在鉴定和鉴定TAO的特性、确定TAO激酶域的结构、识别化学上易处理的抑制剂以及阐明TAO依赖的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，这将为TAO激酶作为药物开发的主题提供基础。