Cytoskeletal Mechanisms of Platelet Formation

血小板形成的细胞骨架机制

• 批准号: 6538082
• 负责人: JOSEPH E ITALIANO
• 金额: $ 33.39万
• 依托单位: BRIGHAM AND WOMEN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-07-01 至 2006-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6538082
• 关键词: biological signal transduction; cell component structure /function; cell differentiation; cell migration; cytoskeletal proteins; cytoskeleton; electron microscopy; enzyme inhibitors; fluorescence microscopy; gene expression; gene targeting; genetically modified animals; histogenesis; laboratory mouse; light microscopy; megakaryocytes; microfilaments; microinjections; microtubules; molecular dynamics; platelets; protein structure function; tissue /cell culture; video microscopy; von Willebrand factor

DESCRIPTION (provided by applicant): Blood platelets play an essential role in hemostasis. The purpose of this proposal is to investigate the cytoskeletal mechanics of platelet formation using a mouse megakaryocyte (MK) culture system. Platelet formation follows a defined set of morphogenetic shape changes driven by microtubules (MTs) and actin filaments within the MK cytoskeleton. It begins with the extension of large pseudopodia from the MK that appear to use cortical bundles of MTs to elongate into proplatelets which ultimately form prominent coils of MTs at their bulbous ends. Linear arrays of MTs that line the proplatelet shaft serve as tracks for the translocation of platelet components into developing platelets. Repeated bending and branching of proplatelets plays a crucial role in platelet formation. This actin-dependent process, which amplifies proplatelet ends, is essential for generating the beaded appearance of proplatelets. This MK culture system will be used to investigate the role of MTs and actin filaments in the mechanics of platelet formation. Aim I will define how MT forces elongate proplatelet processes and determine how the marginal MT coil forms during platelet morphogenesis. Dynamic changes in the MT cytoskeleton will be observed as it functions in living MKs to establish the contribution of MT assembly and/or sliding in proplatelet elongation and MT coil formation. In Aim 2, structural and biochemical methods will be used to characterize and define the mechanism of organelle and granule transport along MTs into developing platelets. Aim 3 will examine the mechanism of actin-dependent proplatelet bending/branching. In the last aim, we will examine platelet morphogenesis at the molecular level and define when the membrane skeleton of the discoid platelet assembles and is locked into place by the vWf receptor-filamin-actin linkage. Understanding the cytoskeletal mechanics of platelet formation may provide insights into how platelets are produced and yield strategies for treatment of thrombocytopenia.

描述(由申请者提供)：血液中的血小板在 止血。这项建议的目的是研究细胞骨架 小鼠巨核细胞(MK)培养条件下的血小板形成机制 系统。血小板的形成遵循一系列明确的形态发生变化 由微管(MT)和MK细胞骨架内的肌动蛋白细丝驱动。它 开始于从MK开始的大伪足的延伸，似乎使用 MTS的皮质束伸长成原血小板，最终形成 突出的卷曲的MTS在他们的球根末端。MTS的线性阵列 原血小板轴作为血小板移位的轨迹 形成发育中的血小板。的反复弯曲和分支 前血小板在血小板形成中起着至关重要的作用。这种肌动蛋白依赖 放大原血小板末端的过程是产生 前血小板的珠状外观。 该MK培养系统将用于研究MTS和肌动蛋白的作用 细丝在血小板形成机制中的作用。AIM I将定义MT如何 作用力延长原血小板突起并决定边缘MT线圈如何 在血小板形态形成过程中形成。金属硫蛋白细胞骨架的动态变化 将被观察，因为它在活的MK中发挥作用，以确定 MT组装和/或在原血小板延长和MT线圈形成过程中滑动。在……里面 目标2，将使用结构和生化方法来表征和 确定细胞器和颗粒沿MTS转运到 发育中的血小板。目标3将研究肌动蛋白依赖的机制 原血小板弯曲/分支。在最后一个目标中，我们将检测血小板 在分子水平上的形态发生，并定义何时膜骨架 盘状血小板组装并被VWF锁定到位 受体-细丝-肌动蛋白连接。了解人的细胞骨架力学 血小板的形成可以提供对血小板是如何产生和 治疗血小板减少症的有效策略。