Structure and Mechanics of Smooth Muscle Thin Filaments

肌动蛋白-细胞骨架是血管平滑肌细胞形状的主要决定因素，有人提出 在细胞收缩和扩张过程中进行重塑。细胞骨架重塑需要 肌动蛋白结合蛋白(ABPs)，稳定、交联、覆盖和/或切断肌动蛋白细丝。低于正常 生理条件血管系统经历广泛的机械力，它是 细胞骨架的相互作用使血管平滑肌细胞能够感知和响应 机械膨胀和压缩(以及这些力量中任何与疾病有关的变化)。的目标是 这项建议是为了确定ABPs对血管细胞骨架的结构和力学效应。 以了解这种重要细胞器的特性。为了阐明这些影响 力对ABP结合的影响以及ABPs对细胞骨架力学的影响，关于 需要单个细胞骨架微丝的分子结构和力学性能。我们的方法将 利用螺旋和单粒子分析来确定肌动蛋白上的ABP结合位点的位置， 从而揭示了肌动蛋白细丝上的ABP之间存在协同或替代的“停滞问题”的可能性。 此外，我们将使原子分辨率结构适合于我们的重建，从而准确地指出关键的 ABPs与肌动蛋白的分子间相互作用。由于ABPS可能会改变细丝结构和 力学方面，将确定ABP结合对肌动蛋白弯曲和扭转刚性的影响。同样， 将评估施加在F-肌动蛋白上的力对ABP与细丝结合的机械效应。这些 结构和物理研究将描述调节细胞骨架的ABPs的分子结构域 动力学和机械行为。这些信息允许我们1)定义必需的残基 用于传递和感知力量的细胞骨架细丝和2)设计PPG使用的诱饵多肽 成员研究血管细胞制剂的生理功能。Layer摘要：收缩和 供应血管的血管平滑肌细胞的维持是起关键作用的因素 用于控制血压和流向人体器官的血液。我们将确定 由微小的细丝组成的细胞内骨架的结构和力学，它控制着 改善血管平滑肌细胞的形状，从而有助于调节血压和血流。

The actin-cytoskeleton is a major determinant of the shape of vascular smooth muscle cells and is proposed to remodel during cell contraction and distension. Cytoskeletal remodeling requires the coordinated action of actin binding proteins (ABPs) that stabilize, crosslink, cap and/or sever actin filaments. Under normal physiological conditions the vascular system experiences a wide range of mechanical forces, and it is the interactions of the cytoskeleton that enable vascular smooth muscle cells to sense and respond to mechanical distension and compression (and any disease related alterations in these forces). The goal of this proposal is to determine structural and mechanical effects of ABPs on the cytoskeleton of vascular smooth muscle cells in order to understand the properties of this essential organelle. To elucidate the effects of force on ABP binding as well as the effects of ABPs on cytoskeletal mechanics, information about the molecular structure and mechanics of the single cytoskeletal microfilaments is required. Our approach will take advantage of helical and single-particle analysis to define the location of ABP binding sites on actin, thus revealing the potential for synergy or alternatively "parking problems" between ABPs on actin filaments. In addition, we will fit atomic resolution structures into our reconstructions, thus pinpointing critical intermolecular interactions between ABPs and actin. Since ABPs may alter both filament structure and mechanics, the effects of ABP binding on actin flexural and torsional rigidity will be determined. Likewise, the mechanical effect of force applied to F-actin on the binding of ABP to filaments will be assessed. These structural and physical studies will characterize the molecular domains of ABPs that regulate cytoskeletal dynamics and mechanical behavior. This information allows us to 1) define residues that are necessary for cytoskeletal filaments to transmit and perceive forces and 2) design decoy peptides to be used by PPG members to investigate physiological function in vascular cell preparations. Lay summary: Contraction and the maintenance offeree by vascular smooth muscle cells that line blood vessels are key factors responsible for controlling blood pressure and blood flow to the organs.of the human body. We will determine the structure and mechanics of an intracellular skeleton composed of microscopic filaments, which control the shape of vascular smooth muscle cells and hence help to regulate blood pressure and blood flow.