ER-to-cell surface transport and signal regulation of GPCRs

GPCR 的 ER 至细胞表面转运和信号调节

• 批准号: 8067914
• 负责人: GUANGYU WU
• 金额: $ 30.07万
• 依托单位: AUGUSTA UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-05-01 至 2014-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8067914
• 关键词: ADP-Ribosylation Factors; Adrenergic Receptor; Agonist; Arginine; Binding; Binding Proteins; Cell Line; Cell Surface Receptors; Cell membrane; Cell physiology; Cell surface; Cells; Disease; Drug Delivery Systems; Drug Design; Ear; Embryo; Endoplasmic Reticulum; Functional disorder; G Protein-Coupled Receptor Signaling; G-Protein-Coupled Receptors; Glioma; Golgi Apparatus; Hormones; Human; Kidney; MAPK3 gene; MEKs; Mediating; Mitogen-Activated Protein Kinases; Modeling; Molecular; Monomeric GTP-Binding Proteins; Neuroblastoma; Pathogenesis; Pathway interactions; Pharmaceutical Preparations; Physiological; Protein Isoforms; Regulation; Role; Signal Pathway; Signal Transduction; Specificity; Transport Vesicles; Tryptophan; Vesicle; adrenergic receptor alpha-2b; human disease; in vivo; novel; public health relevance; receptor; response; spatiotemporal; trafficking; trans-Golgi Network

DESCRIPTION (provided by applicant): The spatiotemporal regulation of intracellular trafficking and signaling of G protein-coupled receptors (GPCRs) is a critical aspect of integrated responses of the cell to hormones. Indeed, defective transport and dysfunction of GPCRs are associated with the pathogenesis of many human diseases. Our overall objective is to define the molecular mechanisms underlying the maturation and signal propagation of GPCRs and their roles in modulating cellular responses to hormones and drugs. Under this broad objective, the focus of the current proposal is to elucidate the mechanisms of nascent GPCR export from the endoplasmic reticulum (ER) to the cell surface and GPCR-mediated activation of the mitogen-activated protein kinase pathway in neuroblastoma-glioma NG108 and human embryonic kidney HEK293 cell lines by using alpha2B-adrenergic receptor (alpha2B-AR) as a model GPCR. We have demonstrated that alpha2B-AR export from the ER is modulated by a highly conserved triple arginine (3R) motif. The 3R motif mediates receptor interaction with selective Sec24 isoforms, components of COPII-coated transport vesicles. Our studies have also revealed a novel function for GGAs [monomeric Golgi-localizing, 3-adaptin ear domain homology, ADP ribosylation factor (ARF)-binding proteins]. GGAs associate with alpha2B-AR and are required for alpha2B-AR transport from the trans-Golgi network (TGN) to the plasma membrane. Furthermore, we have identified a novel signaling pathway in which the di-tryptophan motif-mediated, agonist-dependent interaction of alpha2B-AR with the small GTPase ARF1 dictates the activation of the conventional Raf1-MEK-ERK1/2 cascade by the receptor. The Specific Aims are: 1) to elucidate the mechanism of COPII vesicle-mediated alpha2B-AR export from the ER, 2) to determine the function of GGAs in alpha2B-AR transport from the TGN to the cell surface, and 3) to define the function and mechanism of alpha2B-AR- and ARF1-mediated activation of the Raf1-MEK-ERK1/2 pathway. Overall, these studies will reveal novel molecular mechanisms underlying export trafficking and signal regulation of GPCRs. The information generated from these studies may open new directions for designing drugs to treat diseases involving abnormal trafficking and functioning of GPCRs. PUBLIC HEALTH RELEVANCE: This proposal will study the intracellular trafficking and functional regulation of G protein-coupled receptors. These receptors regulate a variety of cell functions under physiological and pathological conditions and are the targets for drugs to treat many diseases. The successful completion of these studies will open a new direction for designing drugs to treat human diseases involving abnormal trafficking and functioning of G protein-coupled receptors.

描述（由申请人提供）：G蛋白偶联受体（GPCR）的细胞内运输和信号传导的时空调节是细胞对激素的综合反应的关键方面。事实上，GPCR的缺陷转运和功能障碍与许多人类疾病的发病机制相关。我们的总体目标是确定GPCR成熟和信号传播的分子机制及其在调节细胞对激素和药物的反应中的作用。在这个广泛的目标下，目前的建议的重点是阐明新生GPCR输出从内质网（ER）到细胞表面和GPCR介导的活化的丝裂原活化蛋白激酶通路在神经母细胞瘤-胶质瘤NG 108和人胚肾HEK 293细胞系通过使用α 2B-肾上腺素能受体（α 2B-AR）作为模型GPCR的机制。我们已经证明，从ER的α 2B-AR出口是由一个高度保守的三重精氨酸（3R）基序调制。3R基序介导受体与选择性Sec 24亚型（COPII包被的转运囊泡的组分）的相互作用。我们的研究还揭示了GGA [单体高尔基体定位，3-adaptin耳域同源性，ADP核糖基化因子（ARF）结合蛋白]的新功能。GGA与α 2B-AR相关，并且是α 2B-AR从trans-Golgi网络（TGN）转运到质膜所需的。此外，我们已经确定了一种新的信号传导途径，其中α 2B-AR与小GTdR ARF 1的双色氨酸基序介导的激动剂依赖性相互作用决定了受体对常规Raf 1-MEK-ERK 1/2级联的激活。具体目标是：1）阐明COPII囊泡介导的α 2B-AR从ER输出的机制，2）确定GGA在α 2B-AR从TGN转运到细胞表面中的功能，和3）确定α 2B-AR和ARF 1介导的Raf 1-MEK-ERK 1/2途径活化的功能和机制。总体而言，这些研究将揭示新的分子机制的出口贩运和信号调控的GPCR。这些研究产生的信息可能为设计药物治疗涉及异常贩运和GPCR功能的疾病开辟新的方向。 公共卫生相关性：该提案将研究G蛋白偶联受体的细胞内运输和功能调节。这些受体在生理和病理条件下调节多种细胞功能，并且是治疗许多疾病的药物的靶点。这些研究的成功完成将为设计治疗涉及G蛋白偶联受体异常运输和功能的人类疾病的药物开辟新的方向。