REGULATION OF PROTEIN TRAFFICKING IN ADIPOCYTES

脂肪细胞中蛋白质运输的调节

• 批准号: 8443438
• 负责人: MIKE M MUECKLER
• 金额: $ 30.13万
• 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/8443438
• 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; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; 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.

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向质膜再分配的中断是与2型糖尿病相关的外周胰岛素抵抗的近端原因。因此，阐明胰岛素刺激Glut4向质膜的急性再分配的机制所涉及的精确分子途径，可能对理解胰岛素抵抗状态的发病机制具有相当重要的意义。调节Glut4的亚细胞运输部分是由胰岛素应答的AS160/Rab10 GTPase周期决定的，但需要其他未确定的因素来充分解释其基本的细胞内隔离和胰岛素刺激的质膜运动。此外，对Glut4调控亚细胞运输的具体结构特征仍知之甚少。我们已经在Glut4细胞质尾部的羧基端12个残基中发现了一个新的亚细胞靶向基序（LXXLXP），该基序与胰岛素反应性氨基肽酶共享。与其他Glut4靶向基序不同，LXXLXP基序（本文简称IRM，胰岛素应答基序）的改变对转运体的稳态分布有深远的影响，似乎完全取消了其基础循环和胰岛素刺激下的细胞表面易位。该提案的目标是通过描述IRM和假定的akt调节的GTPase激活蛋白AS250在这一过程中的作用来获得对Glut4调控的基本见解。为了实现这一目标，将采取以下具体目标：1)精确定义IRM及其如何与其他已知的Glut4靶向基序相互作用；2)鉴定和表征Glut4移动的新型亚细胞膜区室；3)阐明AS250复合物的功能，胰岛素如何影响其功能，并鉴定AS250/KIAA1219复合物的新成分。