RAB PROTEINS AND CALCIUM AND VESICULAR TRANSPORT

RAB 蛋白与钙和囊泡运输

• 批准号: 2444711
• 负责人: William Edward Balch
• 金额: $ 34.45万
• 依托单位: SCRIPPS RESEARCH INSTITUTE, THE
• 依托单位国家: 美国
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-07-01 至 1999-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2444711
• 关键词: Golgi apparatus; calcium; endoplasmic reticulum; fluorescence spectrometry; guanine nucleotide binding protein; guanine nucleotide exchange factors; guanosine triphosphate; guanosinetriphosphatase activating protein; guanosinetriphosphatases; intracellular membranes; intracellular transport; laboratory mouse; laboratory rabbit; laboratory rat; membrane fusion; molecular chaperones; protein engineering; receptor; secretion; tissue /cell culture; transport proteins; vesicle /vacuole

Rab proteins are small GTPases which function as molecular switches. The GTPase cycle of Rab proteins plays a critical role in the sequential events dictating the formation, targeting and fusion of carrier vesicles mediating protein transport through the constitutive and regulated secretory pathways of eukaryotic cells. Rab1 is critical for the transport of protein between the endoplasmic reticulum (ER) and the cis Golgi compartment, and between cis and medial Golgi compartments. We have identified and partially characterized proteins which interact with Rab1 at different steps in its GTPase cycle. These effectors include: (1) guanine nucleotide dissociation inhibitor (RabGDI) which serves as a cytosolic escort protein, (2) guanine nucleotide exchange protein (Rab1- GEF) which promotes GTP exchange during Rab1 during vesicle formation, and (3) guanine nucleotide activating protein (Rab1-GAP) which promotes GTP hydrolysis, an event likely to be essential for vesicle targeting and fusion. In addition, we have characterized a putative vesicle targeting receptor (syntaxin 5) which links Rab1 function to a late Ca2+-dependent step involved in the docking and fusion of ER-derived carrier vesicles. Highly enriched, ER-derived carrier vesicles have now been generated in vitro and will provide new insight into the function, distribution and composition of Rab1 and its effector proteins. Through the biochemical analysis of specific protein interactions controlled by the Rab1 GDP/GTP switch we will elucidate the functional role of each of these components in the recruitment of vesicle coats during budding from the ER and the assembly of a docking/fusion complex at the target (cis Golgi) acceptor membrane. Given the ubiquitous role of Rab proteins in membrane traffic through the exocytic and endocytic pathways, we anticipate that these studies will provide general insight into the function of the Rab GTPase molecular switch in membrane interactions. Our studies will have important implications for understanding a wide range metabolic disorders affecting the constitutive secretory pathway including cystic fibrosis, alpha-1- anti-trypsin deficiency, and familial hypercholesterolemia.

Rab蛋白是一种小的GTP酶，具有分子开关的功能。的 Rab蛋白的GT3循环在Rab蛋白的连续性免疫应答中起着关键作用。 决定载体囊泡的形成、靶向和融合的事件 介导蛋白质运输通过组成和调节 真核细胞的分泌途径。Rab 1对运输至关重要 内质网（ER）和顺式高尔基体之间的蛋白质 隔室，以及顺式和内侧高尔基室之间。我们有 已鉴定和部分表征的与Rab 1相互作用的蛋白质 在它的GTTT周期的不同阶段。这些效应器包括：（1） 鸟嘌呤核苷酸解离抑制剂（RabGDI），其用作 胞质护送蛋白，（2）鸟嘌呤核苷酸交换蛋白（Rab 1- GEF），其在囊泡形成期间促进Rab 1期间的GTP交换，以及 (3)促进GTP的鸟嘌呤核苷酸激活蛋白（Rab 1-GAP） 水解，可能是囊泡靶向所必需的事件， 核聚变此外，我们已经确定了一个假定的囊泡靶向 受体（syntaxin 5），将Rab 1功能与晚期Ca 2+依赖性 ER衍生载体囊泡的对接和融合中涉及的步骤。 高度富集的ER衍生的载体囊泡现已在 并将提供新的见解的功能，分布和 Rab 1及其效应蛋白。通过生化 Rab 1 GDP/GTP控制的特异性蛋白质相互作用分析 开关，我们将阐明这些组件的功能作用 在从内质网出芽的过程中， 在靶（顺式高尔基体）受体处组装对接/融合复合物 膜的鉴于Rab蛋白在膜运输中的普遍作用， 通过胞吐和胞吞途径，我们预计这些 研究将提供对Rab GTdR功能的一般了解 膜相互作用中的分子开关。我们的研究将对 对理解影响人类健康的多种代谢紊乱的意义 组成性分泌途径包括囊性纤维化，α-1- 抗胰蛋白酶缺乏症和家族性高胆固醇血症。