权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Serine / Threonine Phosphatases and Platelet Physiology

丝氨酸/苏氨酸磷酸酶和血小板生理学

基本信息

批准号：
7837433
负责人：
K. Vinod VIJAYAN
金额：
$ 23.82万
依托单位：
BAYLOR COLLEGE OF MEDICINE
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-07-01 至 2011-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7837433
关键词：
Adhesions Adhesives Binding Binding Proteins Binding Sites Biochemical Biology Blood Platelets Calcium Catalytic Domain Cell Line Cells Chloride Channels Complex Cytoskeletal Modeling Cytoskeleton Enzymes Event Generic Drugs Genes Goals Hemostatic function Human Integrin Binding Integrins Knock-out Knockout Mice Ligand Binding Ligands Maps Mediating Megakaryocytes Membrane Microdomains Molecular Mus Myosin Light Chains Peptides Phosphoric Monoester Hydrolases Phosphorylation Phosphotransferases Physiology Platelet Activation Protein Isoforms Protein Kinase Protein Serine/Threonine Phosphatase Protein phosphatase Proteins RNA Regulation Research Personnel Rest Role Serine Serine/Threonine Phosphorylation Signal Transduction Staging Techniques Testing Threonine Thrombin Thrombosis Thrombus Time Tyrosine Tyrosine Phosphorylation caveolin 1 cofilin genetic regulatory protein inhibitor/antagonist insight knock-down new therapeutic target novel programs protein phosphatase 2C response von Willebrand Factor

项目摘要

Platelet thrombus formation is dependent on inside-out signaling to integrin allbb3 that regulates ligand binding and outside-in signaling through allbbS that controls the platelet cytoskeletal rearrangment. Inside- out and outside-in signaling events involve reversible phosphorylation of tyrosine (Tyr) or serine/threonine (Ser/Thr) residues on multiple proteins. The net Tyr or Ser/Thr phosphorylation of a protein substrate is regulated by the activities of both protein kinases and phosphatases. Historically, kinases and phosphorylation events have held the center stage during integrin-mediated signaling, while a role for the phosphatases is poorly understood. Our preliminary studies demonstrate for the first time that the catalytic subunits of protein phosphatase 1 (PP1c) and protein phosphatase 2A (PP2Ac) but not protein phosphatase 2c (PP2Cc) associate constitutively with the integrin allbbS and regulates allbbS adhesive function. We hypothesize that PP1c and PP2Ac orchestrate a temporal and spatial regulation of integrin allbbS signaling and participate in platelet function. Our goal is to study the mechanisms by which Ser/Thr phosphatases regulate integrin allbbS activation, signaling and function using human platelets, platelets from PP1c null mice, murine megakaryocytes and a cell line with thrombin activatable allbbS (DT40 PAR1/allbb3). Aim 1 will test the hypothesis that PP1c a) dephosphorylates Ser/Thr residues on integrin bS in resting platelets, b) dephosphorylates cofilin thereby activating the cytoskeletal reorganization, and c) is involved in inside-out and outside-in signaling through allbbS. Aim 2 will examine if a) the PP1c-allb interaction modulates the binding of other allb binding proteins, b) the platelet lipid rafts have a role in the spatial regulation of the integrin-phosphatase association. The possibility that PP1c interacts with other integrins bearing the PP1c binding site will be evaluated. Aim 3 will establish the role for PP2Ac in the biology of integrin allbbS. Notably, we will map the PP2Ac binding site on integrin allbbS, study the role of PP2Ac in allbbS inside-out and outside-in signaling. Thus, by elucidating the mechanisms and consequences of allbbS-phosphatase interactions, these studies should provide novel insights into the understudied aspects of platelet function and may provide potential new therapeutic targets for anti-thrombotic therapy.

血小板血栓形成依赖于由内而外的信号传导至调节配体的整合素allbb 3 通过allbbS结合和由外向内信号传导，控制血小板细胞骨架的粘附。在里面- out和outside-in信号传导事件涉及酪氨酸（Tyr）或丝氨酸/苏氨酸的可逆磷酸化 (Ser/Thr）残基。蛋白质底物的净Tyr或Ser/Thr磷酸化是由蛋白激酶和磷酸酶的活性调节。历史上，激酶和磷酸化事件在整联蛋白介导的信号传导过程中占据中心地位，而磷酸化的作用则在整合素介导的信号传导过程中起重要作用。对磷酸酶的了解很少。我们的初步研究首次表明，蛋白磷酸酶1（PP 1c）和蛋白磷酸酶2A（PP 2Ac）的亚基，但不是蛋白磷酸酶 2c（PP 2Cc）与整合素allbbS组成性结合并调节allbbS粘附功能。我们假设PP 1c和PP 2Ac协调整合素allbbS信号传导时间和空间调节并参与血小板功能。我们的目标是研究Ser/Thr磷酸酶调节整合素allbbS活化的机制，使用人血小板、来自PP 1c缺失小鼠的血小板、鼠巨核细胞和人血小板的信号传导和功能，凝血酶可激活的allbbS细胞系（DT 40 PAR 1/allbb 3）。目标1将检验PP 1c a）使静息血小板中整联蛋白bS上的Ser/Thr残基脱磷酸，B）使cofilin脱磷酸，激活细胞骨架重组，以及c）通过以下途径参与由内向外和由外向内的信号传导： allbbS.目的2将检查a）PP 1c-allb相互作用是否调节其他allb结合蛋白的结合， B）血小板脂筏在整合素-磷酸酶结合的空间调节中起作用。的将评估PP 1c与其他带有PP 1c结合位点的整合素相互作用的可能性。目标3将建立PP 2Ac在整合素allbbS生物学中的作用。值得注意的是，我们将PP 2Ac结合位点定位在整合素allbbS，研究PP 2Ac在allbbS由内向外和由外向内信号传导中的作用。因此，通过阐明allbbS-磷酸酶相互作用的机制和后果，研究应该为血小板功能的未充分研究方面提供新的见解，抗血栓治疗的潜在新治疗靶点。