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-I的调节机制。肌球蛋白-I同种型是肌球蛋白超家族的单头、膜相关成员，在大多数真核细胞中发现。肌球蛋白-Is包括在人类中发现的最大的非常规肌球蛋白家族（8个基因）。脊椎动物肌球蛋白-I亚型的大尺寸、多样性和表达谱使其成为最重要的一类非常规肌球蛋白。肌球蛋白在膜动力学、细胞骨架结构、机械信号转导和内体加工中起着重要作用。然而，对这类重要的马达的细胞调节知之甚少。因此，我们的努力在这个建议集中在了解脊椎动物肌球蛋白-I的调节。我们将使用细胞生物学，生物物理学和生物化学技术的组合来研究以下具体目标： 1.肌球蛋白-I与肌球蛋白-I结合蛋白的生化和细胞相互作用。在一个令人兴奋的发现，我们发现了一个家庭的EF-手含有豆蔻酰化蛋白结合肌球蛋白-I亚型。我们将研究这些蛋白质与肌球蛋白I的结合，并研究这些蛋白质在调节肌球蛋白I与细胞膜相互作用中的作用。 2.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与脂质膜结合的机制和调节。我们将研究钙调节肌球蛋白-I与细胞膜结合的能力，并研究肌球蛋白-I螯合对细胞信号传导重要的脂质的能力。 3.肌球蛋白-I的微生物学调节。我们将研究非肌肉原肌球蛋白异构体调节肌球蛋白I的能力。我们将确定是否原肌球蛋白亚型差异调节肌球蛋白-I亚型，我们将确定肌球蛋白-I浓度和原肌球蛋白调节之间的关系。

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.