The Role of Myosin in Vesicle Trafficking

肌球蛋白在囊泡运输中的作用

基本信息

批准号：
7882095
负责人：
YASHOMATI M PATEL
金额：
$ 20.93万
依托单位：
UNIVERSITY OF NORTH CAROLINA GREENSBORO
依托单位国家：
美国
项目类别：
财政年份：
2006
资助国家：
美国
起止时间：
2006-03-01 至 2014-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7882095
关键词：
Actins Address Adipocytes Adipose tissue Affect African American Asian Americans Automobile Driving Biological Assay Calcium/calmodulin-dependent protein kinase Calmodulin Cell membrane Cell physiology Confocal Microscopy Cytoskeletal Modeling Cytoskeleton Development Diabetes Mellitus Disease Elderly Extracellular Signal Regulated Kinases F-Actin Family Fractionation GLUT 4 protein GLUT4 gene Gene Silencing Hispanics Incidence Insulin Insulin Resistance Light Mediating Membrane Microfilaments Mitogen-Activated Protein Kinases Molecular Motor Myosin ATPase Myosin Light Chain Kinase Myosin Type II Native Americans Non-Insulin-Dependent Diabetes Mellitus Nonmuscle Myosin Type IIA Peripheral Pharmacologic Substance Phosphorylation Phosphotransferases Population Prevalence Process Protein Family Protein Isoforms Proteins Public Health Recruitment Activity Regulation Research Role Signal Transduction Site Skeletal Muscle Small Interfering RNA Testing Tissues United States Vesicle base blood glucose regulation calmodulin-dependent protein kinase II cell cortex cell type design effective therapy glucose uptake inhibitor/antagonist insight insulin sensitivity insulin signaling prevent public health relevance trafficking trend type 2 diabetes in children

项目摘要

DESCRIPTION (provided by applicant): Type 2 diabetes is the most prevalent form of diabetes in the United States. The major contributing factor to the development of type 2 diabetes is insulin resistance of peripheral tissues, primarily skeletal muscle and adipose tissue. Insulin mediates the translocation and fusion of insulin-responsive glucose transporter (GLUT4)-containing vesicles to the plasma membrane; this process is critical for proper glucose homeostasis. Thus, the identification and characterization of cellular factors and processes regulating GLUT4 function are critical to understanding the molecular mechanisms underlying impaired insulin sensitivity. While insulin signaling coordinates the translocation and fusion of GLUT4 vesicles by regulating actin reorganization and cytoskeletal remodeling little is known about the cellular contractile forces required for these processes. The broad aim of this proposal is to gain insight on the mechanisms regulating the dynamic reorganization of the cytoskeleton during insulin-stimulated GLUT4 vesicle trafficking. The myosin family of protein, specifically myosin II has been shown to regulate actin filament reorganization to facilitate vesicle trafficking. Our preliminary studies show that the myosin IIA isoform is activated and recruited to the plasma membrane upon insulin stimulation to facilitate GLUT4-mediated glucose uptake. We also have found that insulin regulates myosin IIA via myosin light chain kinase (MLCK), a Ca2+ regulated kinase to promote myosin IIA activation and recruitment to the plasma membrane. Furthermore, we show that inhibition of myosin II activity impairs the proper insertion of GLUT4 at the plasma membrane. Previous studies have shown a requirement for intracellular Ca2+ for insulin stimulated GLUT4 translocation and fusion with the plasma membrane. Based on our findings, we hypothesize that Ca2+ mediates the activation and recruitment of myosin IIA to the cell cortex to facilitate GLUT4 fusion with the plasma membrane. Thus, the specific aims of this proposal are to define and characterize the role of Ca2+ on the regulation of myosin IIA in GLUT4 vesicle trafficking in adipocytes, and to determine the mechanisms by which myosin IIA regulates actin reorganization. PUBLIC HEALTH RELEVANCE: Type 2 diabetes is a major public health issue in the United States affecting approximately 6% of the population. The prevalence of type 2 diabetes is even higher among African Americans, Hispanics, Native Americans, Asian Americans, and the elderly. A particularly alarming trend is the recent dramatic rise in the incidence of type 2 diabetes in children. With the increasing incidence of type 2 diabetes it is critical to identify factors contributing to the development of this disease in order to design effective treatments. The proposed research will provide critical information for understanding the molecular mechanism(s) involved in the development of in type 2 diabetes.

描述（由申请人提供）：2 型糖尿病是美国最流行的糖尿病形式。 2型糖尿病发生的主要因素是外周组织（主要是骨骼肌和脂肪组织）的胰岛素抵抗。胰岛素介导含有胰岛素反应性葡萄糖转运蛋白（GLUT4）的囊泡向质膜的易位和融合；这个过程对于适当的葡萄糖稳态至关重要。因此，调节 GLUT4 功能的细胞因子和过程的识别和表征对于理解胰岛素敏感性受损的分子机制至关重要。虽然胰岛素信号通过调节肌动蛋白重组和细胞骨架重塑来协调 GLUT4 囊泡的易位和融合，但人们对这些过程所需的细胞收缩力知之甚少。该提案的主要目标是深入了解胰岛素刺激的 GLUT4 囊泡运输过程中调节细胞骨架动态重组的机制。肌球蛋白家族，特别是肌球蛋白 II，已被证明可以调节肌动蛋白丝重组，以促进囊泡运输。我们的初步研究表明，肌球蛋白 IIA 亚型在胰岛素刺激后被激活并募集至质膜，以促进 GLUT4 介导的葡萄糖摄取。我们还发现胰岛素通过肌球蛋白轻链激酶 (MLCK) 调节肌球蛋白 IIA，肌球蛋白轻链激酶是一种 Ca2+ 调节激酶，可促进肌球蛋白 IIA 激活和募集到质膜。此外，我们发现肌球蛋白 II 活性的抑制会损害 GLUT4 在质膜上的正确插入。先前的研究表明，胰岛素刺激的 GLUT4 易位和与质膜的融合需要细胞内 Ca2+。根据我们的研究结果，我们假设 Ca2+ 介导肌球蛋白 IIA 的激活和募集到细胞皮质，以促进 GLUT4 与质膜的融合。因此，本提案的具体目的是定义和表征 Ca2+ 对脂肪细胞 GLUT4 囊泡运输中肌球蛋白 IIA 调节的作用，并确定肌球蛋白 IIA 调节肌动蛋白重组的机制。公共卫生相关性：2 型糖尿病是美国的一个主要公共卫生问题，影响约 6% 的人口。非裔美国人、西班牙裔美国人、美洲原住民、亚裔美国人和老年人中 2 型糖尿病的患病率甚至更高。一个特别令人担忧的趋势是最近儿童 2 型糖尿病发病率急剧上升。随着 2 型糖尿病发病率的增加，确定导致该疾病发生的因素以设计有效的治疗方法至关重要。拟议的研究将为理解 2 型糖尿病发展中涉及的分子机制提供关键信息。