Myosin-1 interactions with membranes

描述（由申请方提供）：本提案中详述的研究旨在了解肌球蛋白-1与膜和膜组分在分子水平上的相互作用，并阐明这些相互作用在膜组织和动力学中的作用。肌球蛋白-1家族成员（在人类中表达的八种不同基因）是在膜动力学和其他细胞过程中发挥重要作用的单头马达蛋白。肌球蛋白-1亚型的一个关键特性似乎是它们直接将肌动蛋白细胞骨架连接到细胞膜的能力。几种肌球蛋白-1亚型已被证明可以直接与膜结合，其中一种亚型myo 1c已被证明可以通过其尾部结构域中的假定普列克底物蛋白同源结构域与磷酸肌醇头基紧密结合。鉴于肌球蛋白-1家族在驱动膜动力学中的重要性，值得注意的是，大多数肌球蛋白-1的膜相互作用尚未被探索。因此，本提案的重点是表征肌球蛋白-1-膜相互作用。我们将使用各种生物化学和生物物理技术来检查膜结合特异性，亲和力和动力学。具体目的如下：目的1：肌球蛋白-1家族成员与膜和磷酸肌醇的结合Subaim 1.1：磷酸肌醇结合的表征Subaim 1.2：磷酸肌醇特异性Subaim 1.3：结合动力学膜和肌动球蛋白系统之间的相互作用Subaim 2.1肌动蛋白运动在膜表面的重建Subaim 2.2肌球蛋白-Subaim 2.3肌球蛋白-1与膜中的PIP 2结合的动力学。 公共卫生相关性：肌球蛋白-1家族成员对许多基本细胞过程很重要。在人类中，肌球蛋白-1突变与耳聋有关，而小鼠中的肌球蛋白-1缺失导致对感染、肾脏炎症和肠内皮缺陷的易感性增加。了解肌球蛋白-1与细胞膜脂质成分相互作用的特异性和作用将提供对这些正常和患病生理状态的深入了解。

DESCRIPTION (provided by applicant): The studies detailed in this proposal seek to understand myosin-1 interactions with membranes and membrane components at the molecular level and to elucidate the role of these interactions in membrane organization and dynamics. Myosin-1 family members (eight different genes expressed in humans) are single-headed motor proteins that play essential roles in membrane dynamics and other cellular processes. A key property of myosin-1 isoforms appears to be their ability to directly link the actin cytoskeleton to cell membranes. Several myosin-1 isoforms have been shown to bind directly to membranes, and one isoform, myo1c, has been shown to bind tightly to phosphoinositide headgroups via a putative pleckstrin homology domain in its tail domain. Given the importance on the myosin-1 family in driving membrane dynamics, it is remarkable that the membrane interactions of most of the myosin-1 have been unexplored. Therefore, this proposal is focused on characterizing the myosin-1-membrane interactions. We will use a variety of biochemical and biophysical techniques to examine membrane binding specificities, affinities, and dynamics. The specific aims are as follows: Aim 1: Binding of myosin-1 family members to membranes and phosphoinositides Subaim 1.1: Characterization of phosphoinositide binding Subaim 1.2: Phosphoinositide specificity Subaim 1.3: Kinetics of binding Aim 2: Interplay between membranes and the actomyosin system Subaim 2.1 Reconstitution of actin motility on membrane surfaces Subaim 2.2 Myosin-mediated PIP2 clustering Subaim 2.3 Dynamics of myosin-1 binding to PIP2 in a membrane. PUBLIC HEALTH RELEVANCE: Myosin-1 family members are important for numerous basic cellular processes. In humans, myosin-1 mutations have been linked to deafness, while myosin-1 deletions in mice result in increased susceptibility to infection, kidney inflammation, and defects in the gut endothelium. Understanding the specificity of and roles for myosin-1 interactions with lipid components of the cell membrane will provide insight into these normal and diseased physiological states.