INSULIN REGULATION OF PROTEIN PHOSPHATASE-1 IN NIDDM

我计划在人体中研究胰岛素在体内调节胰岛素分泌的机制， 糖原合酶和蛋白磷酸酶-1磷酸化。具体目标 我将调查的位点特异性丝氨酸磷酸化 导致蛋白质糖原结合亚基的激活 磷酸酶1，随后去磷酸化并激活其 底物，糖原合酶。糖原合酶是最终底物 其被胰岛素激活以开始糖原生成。具体目标 将同样的分析扩展到糖尿病受试者的骨骼肌， 并将他们的反应与我们预期的控制进行比较， 基础和胰岛素刺激后均降低。 所用的临床方法将是正常血糖胰岛素钳夹和骨骼肌胰岛素钳夹。 在两小时胰岛素（或生理盐水）注射前和结束时进行肌肉活检 输液为了分析这两种酶的磷酸化状态， 我们将使用一种新的荧光标记技术 分析在体内的丝氨酸磷酸化模式的变化， 这两个关键的调节酶。 比较这些磷酸化变化的能力在正常和 糖尿病受试者将可能允许治疗干预 旨在使非胰岛素抵抗患者中观察到的胰岛素抵抗正常化， 2型糖尿病

I plan to study in humans the mechanism of insulin's in vivo regulation of glycogen synthase and protein phosphatase-1 phosphorylation. Specific Aim I will be the investigation of the site-specific serine phosphorylation that results in activation of the glycogen-binding subunit of protein phosphatase 1, which subsequently dephosphorylates and activates its substrate, glycogen synthase. Glycogen synthase is the final substrate which is activated by insulin to begin glycogenesis. Specific Aim Il will be extending the same analysis to skeletal muscle in diabetic subjects, and comparing their response to controls which we anticipate will be decreased both basally and after insulin stimulation. The clinical methods used will be a euglycemic insulin clamp, and skeletal muscle biopsies before and at the end of a two hour insulin (or saline) infusion. For analysis of the phosphorylation state of these two enzymes, we will use a new fluorescent-tag technique which allows quantitative analysis of the in vivo changes in the serine phosphorylation pattern of these two key regulatory enzymes. The ability to compare these phosphorylation changes between normal and diabetic subjects will potentially allow for therapeutic interventions designed to normalize the insulin resistance observed in Non-Insulin- Dependent Diabetes Mellitus.