Sterol Regulation of HMG-CoA Reductase Degradation

描述 (申请人摘要)目前的申请是针对事业的 分子遗传学讲师Russell DeBose-Boyd博士的发展 德克萨斯州达拉斯的德克萨斯大学西南医学中心。为应聘者准备参加 研究生涯作为一名独立调查员，职业发展计划是 描述实施指导计划的情况，包括高级 在指导下专注于特定研究项目的研究经验 一位合适的导师。在计划的后期阶段，循序渐进 候选人将成为一名独立的调查员 如果是这样的话。动物脂代谢研究的几点体会 将应用于寄生生物，希望创造出更好的治疗方法 为美国经济贫困社区的感染患者提供服务 国家和第三世界。 过量的甾醇加速HMG-CoA还原酶(HMGCR)的降解，HMGCR是一种主要的 动物细胞中类异戊二烯生物合成调控的重点。这个 拟议的研究旨在检验这样一个假设，即 HMGCR和甾醇诱导蛋白质的构象变化，导致 促进了酶的降解。为了进一步了解这一点 在这一进程中，将追求三个具体目标：(目标1)寻找残留物 对调节类固醇很重要，疏水的NH2-末端结构域 将在基于聚合酶链式反应的策略中对HMGCR进行突变。选拔计划将 用于鉴定导致HMGCR对类固醇耐药的突变 监管。(目标2)将开发一种检测结构变化的方法 在激素治疗的HMGCR中，使用HMGCR特异性抗体和 一组用于探测类固醇诱导的构象变化的蛋白酶组。(目标 3)HMGCR的激素调节与其他激素反应之间的相似性 我们将探索蛋白质。尽管蜂窝网络的一个重要组成部分 膜，胆固醇的过度积累是有毒的，因为它 不解性。血液中过多的胆固醇会沉积在动脉中， 引发动脉粥样硬化，这可能导致心脏病发作。一次彻底的 了解控制HMGCR水平的分子机制可能会提供 对治疗冠心病的新疗法的见解。

DESCRIPTION (Applicant's abstract) The current application is aimed towards the career development of Russell DeBose-Boyd, Ph.D., Instructor of Molecular Genetics at UT Southwestern Medical Center in Dallas, TX. To prepare the candidate for a research career as an independent investigator, a career development plan is described in which a mentored program is undertaken, encompassing an advanced research experience focusing on a specific research project under the guidance of an appropriate mentor. During the later phases of the program, progressive development of the candidate into an independent investigator will be provided. Experiences gained from the study of lipid metabolism in animals will be applied to parasitic organisms in hopes of creating better treatments for infected patients in economically deprived communities of the United States and the Third World. Excess sterols accelerate degradation of HMG-CoA reductase (HMGCR), a major focal point in the regulation isoprenoid biosynthesis in animal cells. The proposed studies are designed to test the hypothesis that interactions between HMGCR and sterols induce conformational changes in the protein, resulting in enhanced degradation of the enzyme. To gain further insight into this process, three specific aims will be pursued: (Aim 1) in search of residues important for mediating sterol-regulation, the hydrophobic NH2-terminal domain of HMGCR will be mutagenized in a PCR-based strategy. A selection scheme will be developed to identify mutations that render HMGCR refractory to sterol regulation. (Aim 2) An assay will be developed to detect structural changes in HMGCR upon sterol treatment, employing HMGCR-specific antibodies and a panel of proteases to probe for sterol-induced conformational changes. (Aim 3) Parallels between sterol regulation of HMGCR and other sterol-responsive proteins will be explored. Although an important component of cellular membranes, over accumulation of cholesterol is toxic because of its insolubility. Excess cholesterol in the bloodstream can deposit in arteries, initiating atherosclerosis, which can lead to heart attacks. A thorough understanding of molecular mechanisms controlling HMGCR levels may provide insights into novel therapies to treat coronary heart disease.