Characterization of human IRS-1 Phosphorylation at S348, T495, and S1005

描述（由申请人提供）：我们实验室的研究重点是人类骨骼肌胰岛素抵抗的机制。具体来说，我们问丝氨酸/苏氨酸磷酸化的信号蛋白IRS-1调节这种蛋白质的功能，这是一个关键的胰岛素在肌肉中的作用。利用灵敏的质谱技术，我们确定了22丝氨酸/苏氨酸磷酸化位点的IRS-1分离自人股外侧肌。我们量化了胰岛素对这些残基中的15个残基的体内磷酸化的影响。在这15个位点中，4个残基，Ser 348，Thr 446，Thr 495和Ser 1005的磷酸化在胰岛素处理后降低。该提案的目的是为Langlais博士提供支持，以确定与瘦的健康对照相比，肥胖和2型糖尿病受试者中胰岛素控制的模式和水平以及人IRS-1中Ser 348、Thr 446、Thr 495和Ser 1005的磷酸化是否失调。该提议的第二个目的是鉴定负责其磷酸化的激酶，其中mTOR是主要的候选激酶。这些实验将提供一个概念框架，在其中放置到上下文中的其他结果，从我们的实验室有关调节这些网站在人体肌肉在体内的磷酸化。因此，朗莱博士的实验将与实验室更大的使命交织在一起。胰岛素抵抗分子机制的定义将提供关于2型糖尿病发病机制的知识，并可能为治疗方式提供分子靶点。 公共卫生相关性：了解胰岛素如何无法在其靶组织（如骨骼肌）中正常发挥作用，将有助于深入了解个体如何发展胰岛素抵抗，2型糖尿病，肥胖和代谢综合征。由于这些疾病是一个日益严重的公共卫生问题，共同负责约40%的公共卫生费用，这些疾病的起源预防和潜在的治疗知识是必要的。

DESCRIPTION (provided by applicant): Research in our laboratory focuses on the mechanisms of insulin resistance in human skeletal muscle. Specifically, we ask how serine/threonine phosphorylation of the signaling protein IRS-1 modulates the function of this protein, which is a key to insulin action in muscle. Using sensitive mass spectrometry techniques, we identified 22 serine/threonine phosphorylation sites in IRS-1 isolated from human vastus lateralis muscle. We quantified the effect of insulin on the in vivo phosphorylation of 15 of these residues. Of these 15 sites, phosphorylation of 4 residues, Ser348, Thr446, Thr495, and Ser1005, was decreased upon insulin treatment. The purpose of this proposal is to provide support for Dr. Langlais to ascertain whether the insulin controlled pattern and level and of phosphorylation of Ser348, Thr446, Thr495, and Ser1005 in human IRS-1 is deregulated in obese and type 2 diabetic human subjects as compared to lean, healthy controls. The second aim of this proposal is to identify the kinase(s) responsible for their phosphorylation, with mTOR being the principal candidate kinase. These experiments will provide a conceptual framework in which to place into context other results from our laboratory regarding regulation of phosphorylation of these sites in human muscle in vivo. Therefore Dr. Langlais' experiments will interweave with the larger mission of the laboratory. Definition of the molecular mechanisms responsible for insulin resistance will provide knowledge regarding the pathogenesis of type 2 diabetes mellitus and potentially provide molecular targets for treatment modalities. PUBLIC HEALTH RELEVANCE: Understanding how insulin fails to function properly in its target tissues, such as skeletal muscle, will provide insight into how individuals develop insulin resistance, type 2 diabetes, obesity, and the metabolic syndrome. Since these diseases are a growing public health problem responsible together for about 40% of public health costs, knowledge of the origins prevention and potential treatments for these diseases are imperative.