REGULATION OF PROTEIN TRAFFICKING IN ADIPOCYTES

脂肪细胞中蛋白质运输的调节

• 批准号: 7765902
• 负责人: MIKE M MUECKLER
• 金额: $ 38万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-03-01 至 2014-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7765902
• 关键词: Accounting; Acute; Adipocytes; Affect; Alanine; Amino Acids; Behavior; Biochemical; Cell membrane; Cell surface; Cells; Complex; Confocal Microscopy; Cytoplasmic Tail; Diabetes Mellitus; Electron Microscopy; Endosomes; Fluorescence; GTPase-Activating Proteins; Gene Silencing; Glucose Transporter; Goals; Golgi Apparatus; Guanosine Triphosphate Phosphohydrolases; Insulin; Insulin Resistance; Label; Lasers; Mediating; Membrane; Metabolic syndrome; Molecular; Movement; Non-Insulin-Dependent Diabetes Mellitus; Obesity; Pathogenesis; Pathway interactions; Pattern; Peripheral; Phenotype; Phosphorylation; Procedures; Process; Protein-Serine-Threonine Kinases; Proteins; Recycling; Regulation; Role; Series; Sorting - Cell Movement; Subcellular Fractions; Techniques; Vesicle; basal insulin; blood glucose regulation; glucose disposal; glucose transport; insight; insulin signaling; magnetic beads; mutant; novel; overexpression; protein complex; protein transport; public health relevance; rat vp165 protein; syntaxin 6; trafficking

DESCRIPTION (provided by applicant): The Glut4 glucose transporter catalyzes the rate-limiting step in postprandial whole body glucose disposal. A disruption in the insulin-stimulated redistribution of Glut4 to the plasma membrane is the proximal cause of the peripheral insulin resistance associated with type 2 diabetes mellitus. Elucidation of the precise molecular pathways involved in the mechanism by which insulin stimulates the acute redistribution of Glut4 to the plasma membrane may thus be of considerable importance in understanding the pathogenesis of insulin resistant states. The regulated subcellular trafficking of Glut4 is partially dictated by the insulin- responsive AS160/Rab10 GTPase cycle, but additional unidentified factors are necessary to fully account for its basal intracellular sequestration and insulin-stimulated movement to the plasma membrane. Additionally, the specific structural features of Glut4 that direct its regulated subcellular trafficking remain poorly understood. We have identified a novel subcellular targeting motif (LXXLXP) within the carboxy-terminal 12 residues of the cytoplasmic tail of Glut4 that is shared with the insulin-responsive aminopeptidase. Unlike other Glut4 targeting motifs, alteration of the LXXLXP motif (herein referred to as IRM, insulin-responsive motif) has a profound effect on the steady-state distribution of the transporter and appears to completely abolish its basal recycling and insulin-stimulated translocation to the cell surface. The goal of this proposal is to gain fundamental insights into Glut4 regulation by delineating the role of the IRM and of a putative Akt-regulated GTPase activating protein, AS250, in this process. In order to accomplish this goal, the following specific aims will be undertaken: 1) to precisely define the IRM and how it interacts with other known Glut4 targeting motifs; 2) to identify and characterize novel subcellular membrane compartments through which Glut4 moves; and 3) to elucidate the function of the AS250 complex, how insulin affects its function, and identify novel components of the AS250/KIAA1219 complex. PUBLIC HEALTH RELEVANCE: This project proposes to investigate novel aspects of how glucose transport is regulated by insulin in fat cells. It is directly relevant to understanding the molecular mechanisms involved in the regulation of whole body glucose homeostasis and its derangement in insulin resistant states such as diabetes, obesity, and metabolic syndrome.

描述（由申请人提供）：GLUT4葡萄糖转运蛋白催化餐后全身葡萄糖处置的限速步骤。胰岛素刺激的GLUT4重新分布到质膜的破坏是与2型糖尿病相关的外周胰岛素抵抗的近端原因。因此，胰岛素刺激Glut4刺激到质膜的急性重新分布的机制中涉及的精确分子途径可能至关重要，这对于理解胰岛素耐药态的发病机理可能非常重要。 GLUT4的受调节的亚细胞运输部分由胰岛素反应的AS160/RAB10 GTPase周期决定，但是需要其他未识别的因素才能充分说明其基础细胞内螯合和胰岛素刺激的运动对质膜膜。此外，指导其监管亚细胞运输的GLUT4的特定结构特征仍然很少理解。我们已经确定了与胰岛素反应性氨基肽酶共享的羧基末端12残基中的新型亚细胞靶向基序（LXXLXP）。与其他GLUT4靶向基序不同，LXXLXP基序的改变（此处称为IRM，胰岛素反应性基序）对转运蛋白的稳态分布产生了深远的影响，并且似乎完全废除了其基础回收和胰岛素刺激的转移到细胞表面。该提案的目的是通过描述IRM和推定Akt调节的GTPase激活蛋白AS250的作用来获得对GLUT4调节的基本见解。为了实现这一目标，将实现以下特定目标：1）精确定义IRM及其与其他已知的GLUT4靶向基序的相互作用； 2）识别和表征GLUT4移动的新型亚细胞膜室； 3）为了阐明AS250复合物的功能，胰岛素如何影响其功能，并确定AS250/KIAA1219复合物的新成分。 公共卫生相关性：该项目建议研究脂肪细胞中胰岛素如何调节葡萄糖转运的新方面。它与了解全身葡萄糖稳态调节及其在胰岛素抵抗状态（如糖尿病，肥胖症和代谢综合征）中的危险中所涉及的分子机制直接相关。