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: 10471913
• 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/10471913
• 关键词: Ablation; Actin-Binding Protein; Actins; Adhesions; Affinity; Binding; Biochemical; Blood; Blood Vessels; Blood coagulation; C-terminal; Cell Adhesion; Cells; Communication; Coupled; Cytoskeleton; Cytosol; Data; Development; Diagnosis; Disease; Event; Extracellular Matrix; Face; Genetic study; Head; Impairment; Integrin Binding; Integrin alpha Chains; Integrins; Laboratories; Lead; Length; Ligands; 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

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.

项目摘要 该建议的长期目标是了解整联蛋白的激活和信号传导机制 - 一类控制细胞 - 托管基质（ECM）粘合剂和 潜水员依赖性的物理和病理过程，例如血管生成，血液衣服， 血栓形成和中风。在四十年前发现的整合素蛋白被深入研究，近75,000 PubMed中的文章。许多实验室已经付出了巨大的努力来研究 整联蛋白激活 - 启动细胞ECM粘合剂的第一个关键步骤，这导致了发现和阐明 关键整合素激活剂塔林 - 一种大的肌动蛋白结合蛋白，其中含有N末端域（Talin-H）和 C末端杆域（TALIN-R）。现在人们普遍认为，塔林利用其塔林 - H结合整合素 细胞质面部以引起“内而外”构象信号激活接收器。但是，最近的飞行员 来自我们实验室的研究表明，组成型活跃的全长塔林更有效 比talin-h激活整联蛋白，挑战仅塔林-H的前提来控制整联蛋白激活。 此外，完整的塔林在细胞质中自动抑制，以及如何募集/激活以激活整合素和链接 整合蛋白到肌动蛋白（外部信号传导），用于促进细胞骨架重新组装和动态粘附 难以捉摸。我们建议以三个高度综合的目标解决这些难题问题。 AIM1将阐明如何 小型GTPase Rap1合作地绑定了塔林-H的塔林F0和F1域，以促进塔林招募和 新生的粘合剂适配器帕西林如何与PIP2协同激活塔林。 AIM2将在此之后调查 激活Talin，Paxillin如何通过将塔林-H和Talin-R桥接到另一个来进一步调节塔林的功能 整合素激活剂Kindlin-2促进有效整联蛋白激活。结果将提供有关如何 Talin R对整联蛋白的激活做出了重大贡献。 AIM3将检查塔林如何介导整联蛋白信号传导 到肌动蛋白细胞骨架 - 长期推测的整合素外部过程，阐明的过程仍然很差。 总之，我们提出的研究有望导致一个新的范式来理解细胞粘附 通过提供对塔林如何调节以进行一系列动态序列的全面看法，来进行机制 激活整联蛋白并将其与肌动蛋白丝链接的事件，导致细胞骨架重新组装和动态粘合剂。 考虑到塔林及其相关蛋白在血栓形成，中风等中的关键参与，我们的研究可能 最终导致为这些疾病提供更好的诊断和治疗。