Project 2- Mechanistic Role of Talin in Cellular Signaling

项目 2 - Talin 在细胞信号转导中的机制作用

• 批准号: 10661636
• 负责人: JUN QIN
• 金额: $ 56.35万
• 依托单位: CLEVELAND CLINIC LERNER COM-CWRU
• 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 2026-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10661636
• 关键词: Ablation; Actin-Binding Protein; Actins; Adhesions; Affinity; Binding; Biochemical; Blood; Blood Vessels; Blood coagulation; C-terminal; Cell Adhesion; Cells; Communication; Coupled; Cytoplasm; Cytoskeletal Modeling; Cytoskeleton; Cytosol; Data; Development; Diagnosis; Disease; Event; Extracellular Matrix; Face; Genetic study; Head; Impairment; Integrin Binding; Integrins; Laboratories; Length; Ligand Binding; Link; Mechanics; Mediating; Membrane; Microfilaments; Molecular Conformation; Monomeric GTP-Binding Proteins; N-terminal; Pathologic Processes; Phosphatidylinositol 4,5-Diphosphate; Physiological Processes; Pilot Projects; Process; Proteins; PubMed; Rod; Role; Signal Transduction; Stroke; Talin; Testing; Therapeutic; Thrombosis; Ubiquitin; angiogenesis; cell motility; insight; mutant; novel; paxillin; receptor; recruit; synergism; transmission process

Project Summary The long-term objective of this proposal is to understand the activation and signaling mechanisms of integrins – a class of heterodimeric transmembrane receptors that control cell-extracellular matrix (ECM) adhesion and diverse adhesion-dependent physiological and pathological processes such as angiogenesis, blood clotting, thrombosis, and stroke. Discovered four decades ago, integrins have been intensively studied with nearly 75,000 articles in PubMed. Tremendous effort has been made by many laboratories to investigate the mechanism of integrin activation – the first key step to initiate the cell-ECM adhesion, which led to the discovery and elucidation of a key integrin activator talin – a large actin-binding protein containing an N-terminal head domain (talin-H) and a C-terminal rod domain (Talin-R). It is now widely believed that talin utilizes its talin-H to bind integrin cytoplasmic face to elicit an “inside-out” conformational signal to activate the receptor. However, a recent pilot study from our laboratory revealed unexpectedly that a constitutively active full length talin is much more potent than talin-H to activate integrins, challenging the talin-H-only premise for controlling the integrin activation. Moreover, intact talin is autoinhibited in the cytosol and how it is recruited/activated to activate integrin and link integrin to actin (outside-in signaling) for promoting cytoskeleton reassembly and dynamic adhesion remains elusive. We propose to resolve these puzzling issues in three highly integrated aims. Aim1 will elucidate how a small GTPase Rap1 cooperatively binds talin F0 and F1 domains of talin-H to facilitate the talin recruitment and how a nascent adhesion adaptor paxillin synergizes with PIP2 to activate talin. Aim2 will investigate that after activating talin, how paxillin further regulates the talin function by bridging its talin-H as well as talin-R to another integrin activator kindlin-2 to promote potent integrin activation. The results would provide novel insight into how talin R contributes significantly to the integrin activation. Aim3 will examine how talin mediates integrin signaling to actin cytoskeleton – a long speculated integrin outside-in process that has remained poorly elucidated. Together, our proposed studies are expected to lead to a new paradigm for understanding the cell adhesion mechanisms by providing a comprehensive view of how talin is regulated to undergo a sequence of dynamic events to activate integrin and link it to actin filaments leading to cytoskeleton reassembly and dynamic adhesion. Given the critical involvement of talin and its associated proteins in thrombosis, stroke, etc., our studies may ultimately lead to the development of better diagnosis and therapeutics for these diseases.

项目概要 该提案的长期目标是了解整合素的激活和信号传导机制 - 一类异二聚体跨膜受体，控制细胞-细胞外基质 (ECM) 粘附和 多种粘附依赖性生理和病理过程，如血管生成、凝血、 四十年前发现的整合素已被深入研究了近 75,000 个。 许多实验室为研究其机制付出了巨大的努力。 整合素激活——启动细胞-ECM粘附的第一个关键步骤，从而导致了这一发现和阐明 关键整合素激活剂talin——一种包含N末端头结构域（talin-H）的大型肌动蛋白结合蛋白和 现在人们普遍认为talin利用其talin-H来结合整合素。 然而，最近的一项试验表明，细胞质表面会引发“由内而外”的构象信号来激活受体。 我们实验室的研究出乎意料地表明，组成型活性全长talin 更有效 比talin-H更能激活整合素，挑战了仅talin-H控制整合素激活的前提。 此外，完整的踝蛋白在胞质溶胶中是自抑制的，以及它如何被招募/激活以激活整合素和连接 整合素与肌动蛋白（由外向内信号传导）促进细胞骨架重组和动态粘附保持 我们建议通过三个高度综合的目标来解决这些令人困惑的问题。 小 GTPase Rap1 协同结合 talin-H 的 talin F0 和 F1 结构域，以促进 talin 募集和 新生的粘附接头桩蛋白如何与 PIP2 协同激活 talin Aim2 将在之后进行研究。 激活踝蛋白，桩蛋白如何通过将其踝蛋白-H和踝蛋白-R桥接到另一个来进一步调节踝蛋白功能 整合素激活剂 kindlin-2 促进有效的整合素激活 该结果将为如何激活整合素提供新的见解。 talin R 对整合素激活有显着贡献 Aim3 将检查 talin 如何介导整合素信号传导。 肌动蛋白细胞骨架——一种长期推测的整合素从外到内的过程，但目前仍不清楚。 总之，我们提出的研究预计将带来理解细胞粘附的新范式 通过提供关于如何调节 talin 经历一系列动态的全面视图来研究机制 激活整合素并将其与肌动蛋白丝连接的事件导致细胞骨架重新组装和动态粘附。 鉴于talin及其相关蛋白在血栓形成、中风等中的关键作用，我们的研究可能 最终导致对这些疾病更好的诊断和治疗的发展。