Cellular regulation of myosin-l

描述（由申请人提供）：本提案的工作重点是确定脊椎动物肌球蛋白- 1的调节机制。肌凝蛋白i亚型是肌凝蛋白超家族的单头、膜相关成员，存在于大多数真核细胞中。肌凝蛋白是人类中发现的最大的非常规肌凝蛋白家族（8个基因）。脊椎动物肌球蛋白- 1亚型的大尺寸、多样性和表达谱使其成为非常规肌球蛋白中最重要的一类。肌球蛋白在膜动力学、细胞骨架结构、机械信号转导和核内体加工中发挥重要作用。然而，我们对这类重要马达的细胞调控知之甚少。因此，我们在本提案中的努力集中在理解脊椎动物肌球蛋白- 1的调节。我们将结合使用细胞生物学、生物物理学和生物化学技术来研究以下具体目标：

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, diversity, and expression profile of vertebrate myosin-I isoforms distinguishes it as one of the most important classes of unconventional myosins. Myosin-Is play essential roles in membrane dynamics, cytoskeletal structure, mechanical signal-transduction, and endosome processing. However, very little is known about the cellular regulation of this important class of motors. Therefore our efforts in this proposal focus on understanding vertebrate myosin-I regulation. 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 myosin-I binding proteins. In an exciting discovery, we found a family of EF-hand-containing myristoylated proteins that bind to myosin-I isoforms. We will investigate the binding of these proteins to myosin-I, and we will examine the role of these proteins in regulating the interaction of myosin-I with cellular membranes. 2. Biochemical and cellular interactions of myosin-I with lipid membranes. We will investigate the mechanism and regulation of myosin-I association with lipid membranes. We will investigate the ability of calcium to regulate the association of myosin-I with membranes, and we will investigate the ability of myosin-I to sequester lipids important for cellular signaling. 3. Microfilament-based regulation of myosin-I. We will investigate the ability of nonmuscle tropomyosin isoforms to regulate myosin-I. We will determine if tropomyosin isoforms differentially regulate myosin-I isoforms, and we will determine the relationship between myosin-I concentrations and tropomyosin regulation.