Sterol Regulation of HMG-CoA Reductase Degradation

描述 （申请人摘要）目前的申请是针对职业 Russell DeBose-Boyd博士的发展，分子遗传学讲师， 德克萨斯州达拉斯的UT西南医学中心。 为候选人准备一个 作为一名独立的研究者，职业发展计划是 其中所描述的辅导计划进行，包括先进的 研究经验集中在指导下的具体研究项目 合适的导师 在计划的后期阶段， 将候选人培养成独立调查员， 提供了 动物脂质代谢研究的几点体会 将应用于寄生生物，希望能创造出更好的治疗方法， 为美国经济贫困社区的受感染患者， 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 调节动物细胞中类异戊二烯生物合成的焦点。 的 拟议的研究旨在检验假设， HMGCR和固醇诱导蛋白质的构象变化，导致 增强酶的降解。 为了进一步了解这一点 在这一过程中，将追求三个具体目标：（目标1）寻找残留物 疏水的NH 2-末端结构域对于介导甾醇调节很重要， 将在基于PCR的策略中诱变HMGCR。 甄选计划将 开发用于鉴定使HMGCR对固醇难治的突变 调控 (Aim 2）将开发一种检测结构变化的方法 在HMGCR中，使用HMGCR特异性抗体和 一组蛋白酶来探测甾醇诱导的构象变化。 （目标 3)HMGCR的固醇调节与其他固醇响应性调节之间的相似性 蛋白质将被探索。 虽然细胞的重要组成部分 膜，过度积累胆固醇是有毒的，因为它 不溶性 血液中过量的胆固醇会存款在动脉中， 引发动脉粥样硬化，这可能导致心脏病发作。 的透彻 对控制HMGCR水平的分子机制的理解可以提供 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.