The Transmembrane Protein Disulfide Isomerase TMX1 Negatively Regulates Thrombosis

血小板功能和凝血的控制是激活和抑制之间的微妙平衡。 机械装置。血小板被多种受体激动剂迅速激活，并在 急性冠脉综合征和其他疾病状态下的血栓形成。同样，自然发生的 抗凝剂是防止纤维蛋白生成和血栓形成的关键。蛋白质二硫键的五个分子 异构酶家族、PdI、ERP57、ERP5、ERP72和ERP46增强IIb3和ERP46的激活 血栓。我们发现了跨膜血栓 发现抑制IIb3激活的PDI家族成员 血小板中PDI家族的成员，TMX1，它 血栓形成。TMX1 是第一个 一部小说中的行为 硫醇氧化成二硫键的机制，是血小板激活的最后一个检查点抑制物 导致IIb3构象变化和纤维蛋白原结合的途径。血栓前PDI是 由血小板和内皮细胞分泌，支持血管损伤部位的纤维蛋白生成。我们 发现TMX1在血小板和内皮细胞上表达， 负面的 促凝剂 与其他PDI相反，TMX1 调节纤维蛋白的生成。TMX1抑制凝血的一个机制是通过限制 内皮细胞和血小板的作用。我们建议研究 T 血管TMX1作为双重阴性 通过解决以下具体目标来调节血小板和凝血。我们将描述1. TMX1在血栓形成中的作用；2.TMX1抑制IIb3活化的机制；3.作用 TMX1在其他血小板PDI和其他血小板表面基质上的结合。使用的主要技术将是 激光诱导血栓形成的损伤模型。我们将研究TMX1负性作用的机制 调节凝血。为了确定TMX1抑制血小板功能的潜在机制 将把血小板基因敲除小鼠模型与基于质谱学的功能鉴定相结合 半胱氨酸。该提案将决定TMX1的工作机制，以及TMX1如何 抵消支持IIb激活的PDI酶3.负调控的特征 TMX1的作用将为PDI酶网络如何调节血栓形成提供新的见解。研究：关于 TMX1如何维持血栓形成和止血之间的平衡将阐明促进 止血和抑制血栓形成，为研究TMX1在疾病状态下的作用提供基础。

The control of platelet function and coagulation is a fine balance between activation and inhibitory mechanisms. Platelets become rapidly activated by multiple receptors agonists and have a central role in thrombosis in acute coronary syndromes, and other disease states. Similarly, naturally occurring anticoagulants are critical in preventing fibrin generation and thrombosis. Fivemembers of theprotein disulfide isomerase (PDI) family of enzymes, PDI, ERp57, ERp5, ERp72 and ERp46 potentiate activation of IIb3 and thrombosis.We discovered atransmembrane member of the PDI family found to inhibit activation of IIb3 and member of the PDI family in platelets, TMX1, which thrombosis. TMX1 is the first acts by a novel mechanism of oxidizing thiols to disulfide bonds and is the last checkpoint inhibitor of the platelet activation pathways that lead to conformational changes in IIb3 and fibrinogen binding. The prothrombotic PDIs are secreted from platelets and endothelial cells and support fibrin generation at the site of vascular injury. We found that TMX1 is expressed on platelets and endothelial cells but, negatively procoagulant in contras to the other PDIs, TMX1 regulates fibrin generation. One mechanism by which TMX1 inhibits coagulation is by limiting the effect of endothelial cells and platelets. We propose to study t vascular TMX1 as a dual negative regulator of platelets and coagulation by addressing the following Specific Aims. We will characterize 1. the role of TMX1 in thrombus formation; 2. the mechanism of inhibition of IIb3 activation by TMX1; 3. the effect of TMX1 on the other platelet PDIs, and on other platelet surface substrates. A principal technique used will be the laser-induced injury model of thrombosis. We will study the mechanism by which TMX1 negatively regulates coagulation. To determine the underlying mechanisms by which TMX1 inhibits platelet function we will integrate a platelet knockout mouse model with mass spectrometry-based identification of functional cysteines. This proposal will determine the mechanisms by which TMX1 works, and how TMX1 counterbalances the PDI enzymes that support activation of IIb3. Characterization of the negative regulatory role of TMX1 will provide novel insight into how the network of PDI enzymes regulate thrombosis. Studies on how TMX1 maintains the balance between thrombosis and hemostasis will elucidate optimal ways to promote hemostasis and inhibit thrombosis and provide a basis for studying TMX1 in disease states.