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（由应用提供）：该建议的重点是了解分子组成，作用机理以及哺乳动物内质网（ER） - 孔线膜膜接触位点（MCSS）的通信方式。越来越多的证据表明，ER MCS是关键的调节中心，但在分子和功能水平上的定义很差。我将通过检查新描述的成型ER MCS蛋白的哺乳动物同源物（称为LOC（脂质转移在Organelle接触位点），该类别的哺乳动物同源物，该蛋白在我们的实验室（YLOC）中鉴定出来。我们已经证明，体内Ylocs直接有利于ER和许多其他细胞器之间的膜接触，并且体外Ylocs介导脂质体之间的非维化立体声转运。我的初步数据表明，哺乳动物LOC（MLOC）家族成员gramd2定位于Ca2+依赖性的ER-PlasmaMmbrane（PM）MCSS，该膜功能可调节存储稳定的Ca2+进入（SOCE）。 SOCE是一种PM Ca2+影响途径，它是由Ca2+从ER存储中耗尽的诱导的，对于细胞稳态至关重要。在此观察结果和我们的YLOC数据的基础上，我将 专注于了解MCSS MLOC的分子基础和功能。具体而言，在AIM 1中，我将在Ca2+调节的ER-PM触点下检查GRAMD2的功能作用。在AIM 2中，我将定义分子活性和grAMD2的机械作用。在AIM 3中，我将探究其他MLOC蛋白质家族成员的功能作用，并检查其在ER MCSS的关系。了解MLOC的基本作用将告知MCSS调节和组成，将为ER MCS在细胞生理学中的作用提供基本的见解，这将改善我们对病因学人类疾病的理解，并可以揭示新的治疗目标。