Cellular regulation of myosin-I

肌球蛋白-I 的细胞调节

• 批准号: 7679738
• 负责人: E. Michael Ostap
• 金额: $ 32.09万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-08-01 至 2011-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7679738
• 关键词: Actin-Binding Protein; Actins; Binding; Biochemical; Biological; Cells; Cellular Mechanotransduction; Endosomes; Eukaryotic Cell; Family; Genes; Genetic Transcription; Goals; Head; Human; Investigation; Kinetics; Learning; Lipids; Mechanics; Membrane; Membrane Lipids; Microfilaments; Molecular; Molecular Profiling; Motor; Muscle; Myosin ATPase; Myosin Type I; Nuclear; Phosphatidylinositols; Play; Process; Property; Protein Isoforms; Regulation; Role; Signal Transduction; Specificity; Structure; Techniques; Tropomyosin; base; cell growth regulation; cell motility; density; member; physical property; sensor

DESCRIPTION (provided by applicant): Efforts in this proposal focus on determining the mechanisms of regulation of vertebrate myosin-I. Myosin-I isoforms are the single-headed, membrane-associated members of the myosin superfamily that are found in most eukaryotic cells. Myosin-Is comprise the largest unconventional myosin family found in humans (eight genes). The large size and expression profile of the vertebrate myosin-I family distinguishes it as one of the most diverse classes. Myosin-Is play essential roles in membrane dynamics, cytoskeletal structure, mechanical signal-transduction, endosome processing, and possibly nuclear transcription. We are only now learning the molecular roles and modes of regulation of this important class of motors. Therefore, our efforts in this proposal focus on understanding the physical properties of vertebrate myosin-I isoforms and the regulation of these properties. We will use a combination of cell biological, biophysical, and biochemical techniques to investigate the following specific aims: 1. Biochemical and cellular interactions of myosin-I with lipid membranes. We will investigate the specificity of myosin-I isoforms for signaling lipids, we will determine the kinetics of phosphoinositide binding and release, and we will determine the motile interactions of myosin-I isoforms with membranes. 2. Microfilament-based regulation of myosin-I. Non-muscle tropomyosin plays an important role in regulating myosin-I localization and activity, but very little is known about this fundamental mode of regulation. We will investigate the biochemical details of the tropomyosin and myosin-I interaction with the goal of understanding the cellular regulation of myosin-I by microfilaments. 3. Characterization of myosin-I as a tension-sensor. Myosin-I is a low-duty ratio motor in the absence of load. However, our new investigations show that under small loads, the lifetime of actin attachment is increased dramatically, such that it becomes a high duty ratio motor. We will investigate the role of force and motor density in regulating processive motility, and we will investigate the mechanical diversity within the myosin-I family.

描述（由申请人提供）：本提案的重点是确定脊椎动物肌球蛋白-I 的调节机制。肌球蛋白-I 亚型是肌球蛋白超家族中与膜相关的单头成员，存在于大多数真核细胞中。肌球蛋白-Is 包含人类中发现的最大的非常规肌球蛋白家族（八个基因）。脊椎动物肌球蛋白-I 家族的大尺寸和表达谱使其成为最多样化的类别之一。肌球蛋白-Is 在膜动力学、细胞骨架结构、机械信号转导、内体加工以及可能的核转录中发挥着重要作用。我们现在才了解这一类重要电机的分子作用和调节模式。因此，我们在本提案中的努力重点是了解脊椎动物肌球蛋白-I 亚型的物理特性以及这些特性的调节。我们将结合细胞生物学、生物物理和生化技术来研究以下具体目标： 1. 肌球蛋白-I 与脂质膜的生化和细胞相互作用。我们将研究肌球蛋白-I 亚型对于信号脂质的特异性，我们将确定磷酸肌醇结合和释放的动力学，并且我们将确定肌球蛋白-I 亚型与膜的运动相互作用。 2. 基于微丝的肌球蛋白-I 调节。非肌肉原肌球蛋白在调节肌球蛋白-I 定位和活性方面发挥着重要作用，但人们对这种基本调节模式知之甚少。我们将研究原肌球蛋白和肌球蛋白-I 相互作用的生化细节，目的是了解微丝对肌球蛋白-I 的细胞调节。 3. 肌球蛋白-I 作为张力传感器的表征。 Myosin-I 是无负载时的低占空比电机。然而，我们的新研究表明，在小负载下，肌动蛋白附着的寿命显着增加，从而成为高占空比电机。我们将研究力和运动密度在调节过程运动中的作用，并将研究肌球蛋白-I 家族内的机械多样性。