MECHANISTIC AND FUNCTIONAL ROLES OF ER-PM CONTACT SITES

ER-PM 接触点的机械和功能作用

• 批准号: 9245561
• 负责人: Marina Besprozvannaya
• 金额: $ 5.71万
• 依托单位: UNIVERSITY OF CALIFORNIA AT DAVIS
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-04-01 至 2018-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9245561
• 关键词: Ablation; Active Sites; Address; Affect; Affinity; Alleles; Architecture; Area; Biological Assay; Cell membrane; Cell physiology; Cells; Cellular biology; Clustered Regularly Interspaced Short Palindromic Repeats; Communication; Data; Endoplasmic Reticulum; Etiology; Failure; Family member; Fluorescence Microscopy; Fostering; Functional disorder; Homeostasis; In Vitro; Knock-out; Lead; Lipid Binding; Lipids; Liposomes; Malignant Neoplasms; Mammalian Cell; Mediating; Membrane; Membrane Proteins; Mission; Molecular; Mutate; Mutation; Neurodegenerative Disorders; Organelles; Pathway interactions; Phosphatidylinositol Phosphates; Physiology; Play; Process; Property; Protein Family; Proteins; Proteomics; Recombinants; Recruitment Activity; Regulation; Research; Resolution; Role; Signal Transduction; Site; Specificity; Sterols; United States National Institutes of Health; Work; Yeasts; cell growth regulation; experimental study; genome editing; human disease; improved; in vivo; insight; interest; lipid transfer protein; lipid transport; member; mutant; new therapeutic target; public health relevance; sensor; targeted treatment

 DESCRIPTION (provided by applicant): This proposal is focused on understanding the molecular composition, mechanism of action, and modes of communication of mammalian endoplasmic reticulum (ER)-organelle membrane contact sites (MCSs). Increasing evidence indicates that ER MCSs are crucial regulatory hubs, but they are poorly defined on both the molecular and functional levels. I will address this deficit by examining the mammalian homologs of a newly described class of conserved ER MCS proteins, termed Loc (lipid transfer at organelle contact site), identified in our lab in yeast (yLoc). We have demonstrated that in vivo yLocs directly facilitate membrane contacts between the ER and many other organelles and in vitro yLocs mediate the non-vesicular sterol transport between liposomes. My preliminary data reveal that the mammalian Loc (mLoc) family member GRAMD2 localizes to Ca2+-dependent ER-plasma membrane (PM) MCSs, which function to regulate store-operated Ca2+ entry (SOCE). SOCE is a PM Ca2+ influx pathway that is induced by depletion of Ca2+ from ER stores and is critical for cell homeostasis. Building on this observation and our yLoc data, I will focus on understanding the molecular basis and functions of mLocs at ER MCSs. Specifically, in Aim 1, I will examine the functional role of GRAMD2 at Ca2+-regulated ER-PM contacts. In Aim 2, I will define molecular activities and the mechanistic role of GRAMD2. In Aim 3, I will probe the functional role of other mLoc protein family members and examine their relationships at ER MCSs. Understanding the fundamental role of mLoc will inform upon MCSs regulation and composition will provide fundamental insight into the roles of ER MCSs in cell physiology, which will improve our understanding of the etiology human disease and could reveal new targets for therapeutics.

 描述（由申请人提供）：该提案的重点是了解哺乳动物内质网（ER）-细胞器膜接触位点（MCS）的分子组成、作用机制和通讯模式，越来越多的证据表明 ER MCS 是至关重要的调节剂。中枢，但它们在分子和功能水平上的定义都很差，我将通过检查新描述的一类保守 ER MCS 蛋白（称为 Loc）的哺乳动物同源物来解决这一缺陷。 （细胞器接触位点的脂质转移），在我们的酵母实验室（yLoc）中发现。我们已经证明，体内 yLocs 直接促进 ER 和许多其他细胞器之间的膜接触，体外 yLocs 介导脂质体之间的非囊泡甾醇转运。我的初步数据表明，哺乳动物 Loc (mLoc) 家族成员 GRAMD2 定位于 Ca2+ 依赖性 ER 质膜 (PM) MCS，其功能调节钙池操纵的 Ca2+ 进入 (SOCE) 是一种 PM Ca2+ 流入途径，它是由 ER 储存的 Ca2+ 耗尽引起的，对于细胞稳态至关重要。 具体来说，在目标 1 中，我将研究 GRAMD2 在 Ca2+ 调节的 ER-PM 接触中的功能作用。在目标 2 中，我将定义分子活性和机制作用。在目标 3 中，我将探讨其他 mLoc 蛋白家族成员的功能作用，并检查它们在 ER MCS 中的关系，了解 mLoc 的基本作用。 MCS 的调节和组成将为了解 ER MCS 在细胞生理学中的作用提供基础见解，这将提高我们对人类疾病病因学的理解，并可能揭示新的治疗靶点。