PILOT STUDY--MOLECULAR MECHANISMS OF APOLIPOPROTEIN B BIOGENESIS

我们建议研究载脂蛋白B(Apo B)的过程。 生物发生和脂蛋白颗粒的形成。载脂蛋白B， 在肝脏和肠道中合成，在胆固醇中起主要作用 运输。高胆固醇血症是动脉粥样硬化的主要危险因素 和冠状动脉疾病。一组血清水平升高的患者 胆固醇在载脂蛋白B结构上有缺陷，而其他许多人有 含载脂蛋白B的代谢和清除过程中的未知异常 脂蛋白。对这些缺陷的分子理解将需要 详细了解正常脂蛋白颗粒的作用机制 已经组装好了。尽管在理解将军的问题上取得了重大进展 蛋白质的生物发生机制--脂蛋白的特定过程 大会在很大程度上仍然是未知的。我们将部分和全部寄送 两种膜补充型无细胞体系中载脂蛋白B编码基因的克隆 在活细胞(非洲爪哇卵母细胞)中。载脂蛋白B生物发生的中间体， 通过脉冲追逐免疫沉淀鉴定，将与 载脂蛋白B跨内质网膜的转位和 脂蛋白颗粒组装。这些初步研究将启动一个项目 目的是解剖和重建载脂蛋白B易位，组装， 细胞内运输和分泌。通过这项工作，将出现一种 载脂蛋白B和载脂蛋白B生物发生过程的分子描述 与之相关的脂蛋白颗粒。这一理解将 最终提供对反常粒子可能的作用的洞察 在人类脂蛋白紊乱中的组装。

We propose to investigate the processes of apolipoprotein B (apo B) biogenesis and lipoprotein particle formation. Apolipoprotein B, synthesized in liver and intestine, plays a major role in cholesterol transport. Hypercholesterolemia is a major risk factor for atherosclerosis and coronary artery disease. A subset of patients with elevated serum cholesterol have defects in apo B structure, while many others have uncharacterized aberrations in metabolism and clearance of apo B containing lipoproteins. A molecular understanding of these defects will require detailed knowledge of the mechanism by which a normal lipoprotein particle is assembled. Despite major progress in understanding the general mechanisms of protein biogenesis, the specific process of lipoprotein assembly remains largely unknown. We will express partial and full-length cloned cDNAs encoding apo B in both membrane-supplemented cell-free systems and in living cells (Xenopus oocytes). Intermediates in apo B biogenesis, identified by pulse-chase immunoprecipitation, will be related to stages in apo B translocation across the endoplasmic reticulum membrane and lipoprotein particle assembly. These pilot studies will initiate a program aimed at dissection and reconstitution of apo B translocation, assembly, intracellular transport and secretion. Through this work will emerge a molecular description of events in the biogenesis of apo B and the lipoprotein particles with which it is associated. This understanding will ultimately provide insight into possible roles for aberrant particle assembly in lipoprotein disorders of humans.