Erlins in regulation of cholesterol-based endoplasmic reticulum functions

Erlins 调节基于胆固醇的内质网功能

• 批准号: 8111656
• 负责人: Larry R. Gerace
• 金额: $ 28.49万
• 依托单位: SCRIPPS RESEARCH INSTITUTE, THE
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-06-01 至 2013-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8111656
• 关键词: Behavior; Binding; Biochemical; Biological Assay; Cardiovascular Diseases; Cell membrane; Cell physiology; Cells; Cellular biology; Ceramides; Chemicals; Cholesterol; Cholesterol Homeostasis; Complement; Complex; Cultured Cells; Data; Detergents; Elements; Endoplasmic Reticulum; Fluorescence Recovery After Photobleaching; Fractionation; Future; Genetic Transcription; Golgi Apparatus; Human; Intracellular Membranes; Light; Link; Lipids; Low-Density Lipoproteins; Mammalian Cell; Mass Spectrum Analysis; Membrane; Molecular; Organism; Outcome; Pathway interactions; Play; Property; Proteins; Recombinants; Regulation; Resistance; Role; SRE-2 binding protein; Serum; Sterols; Structure; Work; base; cardiovascular disorder risk; cholesterol biosynthesis; cholesterol control; crosslink; in vivo; member; mutant; receptor; response; sensor; steroid hormone; transcription factor; uptake

DESCRIPTION (provided by applicant): Cholesterol plays a key role in humans and many other organisms, by serving as a structural element of membranes and by providing a precursor for steroid hormones. Since elevated LDL-associated serum cholesterol is linked to greatly increased risk of cardiovascular disease in humans, understanding the molecular basis for cholesterol homeostasis is of major importance. The SREBP-2 pathway controls cholesterol synthesis and uptake by cells. Core components of the cholesterol sensing machinery in the endoplasmic reticulum (ER) that regulate the activation of SREBP-2 have been characterized in detail. In contrast, little is known about certain other aspects of their regulation, including whether these components are regulated by protein/lipid nanodomains in the ER. Erlin-1 and erlin-2 are closely related ER proteins that fractionate with cholesterol-rich, detergent-resistant membranes. Erlins previously have been linked to ER-associated degradation of the IP3 receptor. Based on recent biochemical and functional results linking erlins to the SREBP-2 pathway, this project will investigate the hypothesis that erlins organize cholesterol-rich, membrane raft-like nanodomains in the ER that are important for regulation of cholesterol biosynthesis. The work will generate erlin-2 mutants that are predicted to be deficient in organizing these nanodomains. These mutants will be analyzed for their ability to partition into a detergent-resistant raft fraction, and to complement the loss of sterol-sensitive regulation of SREBP-2 that is induced by the silencing of endogenous erlins. Additional work will analyze the ability of recombinant wild-type erlin-2 and erlin-2 mutants deficient in raft formation to directly bind cholesterol and ceramide, and will investigate the components of the SREBP-2 machinery that are nearest neighbors of erlins by crosslinking and mass spectrometry. Together, these studies are expected to delineate major features of erlins that underlie their role in organizing ER rafts and in regulating the SREBP-2 pathway. Thus, the work should shed light on a previously unrecognized mechanism involving ER nanodomains that may be crucial for regulation of cholesterol biosynthesis. PUBLIC HEALTH RELEVANCE: Although cholesterol plays a key role in the structure and functions of cells, elevated LDL- associated serum cholesterol is linked to greatly increased risk of cardiovascular disease in humans. This project will analyze new cellular mechanisms implicated in regulating cell cholesterol. This work is relevant for understanding and controlling cholesterol-related cardiovascular diseases.

描述（由申请人提供）：胆固醇在人类和许多其他生物中起着关键作用，它是膜的结构元素，并通过为类固醇激素提供前体。由于升高的LDL相关血清胆固醇与人类心血管疾病的风险大大增加有关，因此了解胆固醇稳态的分子基础至关重要。 SREBP-2途径控制细胞的胆固醇合成和摄取。详细介绍了调节SREBP-2激活的内质网（ER）中胆固醇传感机械的核心成分。相比之下，对其调节的某些其他方面知之甚少，包括这些成分是否受ER中蛋白/脂质纳米构的调节。 ERLIN-1和ERLIN-2是与富含胆固醇，耐洗涤剂的膜分馏的紧密相关的ER蛋白。 Erlins先前已与IP3受体的ER相关降解有关。基于将Erlins与SREBP-2途径联系起来的最新生化和功能结果，该项目将研究ER中ERLINS组织胆固醇富含胆固醇，膜木筏样的纳米域的假设，对于调节胆固醇生物合成很重要。这项工作将产生ERLIN-2突变体，这些突变体预计将缺乏组织这些纳米域。将分析这些突变体的能力，以分配到耐洗涤剂的筏分数中，并补充由内源性Erlins沉默引起的Srebp-2的固醇敏感性调节的损失。其他工作将分析重组野生型ERLIN-2和ERLIN-2突变体缺乏筏形成以直接结合胆固醇和神经酰胺的能力，并将研究SREBP-2机械的成分，这些SREBP-2机械的成分是通过交联和质谱仪的Erlins最近邻居的邻居。总之，这些研究有望描绘出Erlins的主要特征，这些特征是它们在组织ER筏和调节SREBP-2途径方面的作用。因此，这项工作应阐明涉及ER纳米域的先前未认识的机制，这对于调节胆固醇生物合成至关重要。 公共卫生相关性：尽管胆固醇在细胞的结构和功能中起关键作用，但升高的LDL-相关血清胆固醇与人类心血管疾病的风险大大增加有关。该项目将分析与调节细胞胆固醇有关的新细胞机制。这项工作与理解和控制与胆固醇相关的心血管疾病有关。