Role of caveolae in signaling in fat cells

小窝在脂肪细胞信号传导中的作用

• 批准号: 6777634
• 负责人: PAUL F PILCH
• 金额: $ 32.6万
• 依托单位: BOSTON UNIVERSITY MEDICAL CAMPUS
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-08-15 至 2006-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6777634
• 关键词: adipocytes; biological signal transduction; caveolas; cell component structure /function; cell differentiation; cell membrane; chemical kinetics; cryoelectron microscopy; fatty acid binding protein; gene expression; glucose transporter; high performance liquid chromatography; hormone regulation /control mechanism; insulin; intermolecular interaction; laboratory rat; lipid metabolism; lipid transport; mass spectrometry; molecular site; protein purification; protein sequence; protein structure function; proteomics; tissue /cell culture; transport proteins

DESCRIPTION: (provided by applicant) Obesity is the major factor predisposing people to insulin resistance and type II diabetes, despite the fact that it is the failure of skeletal muscle to respond to insulin which prevents glucose uptake and results in hyperglycemia and diabetes. From a mechanistic viewpoint, it is the availability of lipids (fatty acids) from fat stores that produces muscle insulin resistance, in part if not entirely. Insulin resistant skeletal muscles contain more fat than normal muscle, and acute perfusion of fatty acids into muscle will rapidly produce this resistance. Indeed, Richard Bergman and colleagues have postulated that inhibition of lipid release from fat cells is rate limiting with respect to insulin's organismal actions (the so-called single gateway hypothesis to explain the rate limiting step of insulin action). Dennis MeGarry has also emphasized the role of free fatty acids in muscle insulin resistance and the failure, in diabetes, of insulin to suppress fatty acid release from adipocytes. Moreover, the recent discovery of the role of the adipocyte with regard to leptin secretion has added further to the importance of this cell in the regulation of metabolic homeostasis. Thus, while there remains incomplete agreement about cause and effect in type II diabetes, no one would argue that obesity and fat cell metabolism are not critically relevant. The mechanism(s) by which fatty acids are taken up (and released) by adipocytes is not clear. Published data as well as data in this application suggest that structures abundant in adipocytes, called caveolae, may be the Site of lipid (fatty acid) entry and egress in these cells and may play a role in regulating lipid flux. Caveolae (little caves) are sac like structures that protrude into the cell interior from the cell surface. They are an anatomical feature of most cells whose overall physiological role is still unclear and controversial. It has been shown that caveolae bind fatty acids, and caveolae have been postulated as the site of cholesterol release from cells. We have raised a novel monoclonal antibody with which we can irnmuno-isolate caveolae. We are using this new tool to characterize the composition and physiological function of caveolae. In support of a role for caveolae in lipid metabolism, we have identified a putative fatty acid Lransporter (FAT/CD36) as a major protein component. We propose three specific aims: 1. to further characterize the protein constituents of caveolae in primary and cultured adipocytes. 2. to determine the physiological function of these proteins. 3. to modulate the expression of caveolae and determine the effects of this on the function of specific proteins as weU as on overall fat cell metabolism. Such studies address fundamental questions concemin2 insulin resistance as well as the cell biologv of caveolae.

描述：（申请人提供）肥胖是诱发糖尿病的主要因素 胰岛素抵抗和II型糖尿病，尽管事实上， 骨骼肌对阻止葡萄糖生成的胰岛素反应的失败 摄取并导致高血糖症和糖尿病。从机械的角度来看， 正是从脂肪储存中获得的脂质（脂肪酸）产生了 肌肉胰岛素抵抗，部分，如果不是全部。胰岛素抵抗骨骼肌 肌肉比正常肌肉含有更多的脂肪， 会迅速产生这种阻力。理查德·伯格曼和 他的同事们推测，抑制脂肪细胞的脂质释放， 速率限制相对于胰岛素的生物体作用（所谓的 解释胰岛素作用的限速步骤的单通道假说）。 Dennis MeGarry还强调了游离脂肪酸在肌肉中的作用， 胰岛素抵抗和糖尿病中胰岛素不能抑制脂肪 脂肪细胞释放酸。此外，最近发现的作用， 脂肪细胞的瘦素分泌进一步增加了重要性， 在调节代谢平衡中的作用。因此，虽然在 关于II型糖尿病的因果关系仍然不完全一致，没有人 会认为肥胖和脂肪细胞代谢并不重要。 脂肪细胞摄取（和释放）脂肪酸的机制 还不清楚。已发表的数据以及本申请中的数据表明， 脂肪细胞中丰富的结构，称为小窝，可能是脂质的位点。 （脂肪酸）在这些细胞中的进入和排出，并可能在调节 脂质通量小穴（小洞穴）是囊状结构，突出到 从细胞表面分离细胞内部。它们是大多数人的解剖学特征 细胞的整体生理作用仍然不清楚和有争议。它 已经证明小窝结合脂肪酸，并且小窝已经被 被假定为细胞释放胆固醇的部位。我们已经提出了一个 新的单克隆抗体，我们可以免疫分离小窝。我们 利用这种新的工具来表征组成和生理功能 关于Caveolae为了支持小窝在脂质代谢中的作用，我们 鉴定了推定的脂肪酸Ltransporter（FAT/CD 36）作为主要蛋白质 成分我们提出三个具体目标：1。为了进一步表征 原代和培养的脂肪细胞中小窝的蛋白质成分。2.到 确定这些蛋白质的生理功能。3.以调制 表达的小窝，并确定这对功能的影响， 特定的蛋白质对整个脂肪细胞代谢的影响。此类研究 解决有关胰岛素抵抗以及细胞 窖的生物学