MODULATION OF INSULIN RECEPTOR FUNCTION

工作总结：胰岛素electin多效性和 高度整合的一系列代谢和促有丝分裂反应，通过其 细胞内信号系统胰岛素结合后， 胰岛素受体的酪氨酸激酶活性被激活，从而 导致受体及其底物的磷酸化， 酪氨酸残基。这些细胞内底物的磷酸化 导致它们与含有SH 2结构域的分子结合， 产生下游信号。 导致 组织对胰岛素反应的特征性减弱（也称为 胰岛素抵抗）在肥胖相关的2型糖尿病患者被认为 位于胰岛素受体的下游。然而，有证据表明， 提出的支持这一概念，即维持 胰岛素受体的稳态磷酸化可能代表一种 治疗病理性胰岛素的有效途径 阻力使用来自独特序列的合成肽 在胰岛素受体胞质结构域，我们已经确定了一个 肽（称为肽HC）能够选择性地增强 胰岛素受体在体外和完整细胞中均起作用， 对胰岛素样生长因子1（IGF-1）受体无影响 功能我们还报道了该肽与胰岛素的结合 细胞中的受体β亚基，从而提供了为数不多的证据之一， 用于受体结构域之间的协同相互作用。我们 一个实验室最近开发了一种微基因方法， 受体片段的稳定表达，所述受体片段可以特异性地 调节细胞中的胰岛素受体功能。另外，一个变种人 缺乏这种受体片段的胰岛素受体， 构建并在中国仓鼠卵巢细胞中稳定表达。 我们计划研究这种突变对胰岛素的影响 受体介导的信号，并确定是否引入 通过小基因方法缺失的片段将恢复胰岛素 对控制水平的反应。

Summary of work: Insulin elicits pleiotropic and highly integrated series of metabolic and mitogenic responses via its intracellular signaling systems. Upon insulin binding, the intrinsic tyrosine kinase activity of the insulin receptor is activated, thereby leading to phosphorylation of the receptor and its substrates on tyrosine residues. Phosphorylation of these intracellular substrates leads to their association with SH2 domain-containing molecules to generate downstream signals. The defect that causes the characteristic diminution of tissue responses to insulin (also termed insulin resistance) in obesity-related type 2 diabetics is thought to be downstream of the insulin receptor. However, evidence has been presented which supports the notion that maintaining the steady-state phosphorylation of the insulin receptor may represent a valid therapeutic approach for attacking pathologic insulin resistance. Using synthetic peptides derived from unique sequences in the insulin receptor cytoplasmic domain, we have identified a peptide (termed peptide HC) capable of enhancing selectively insulin receptor function both in vitro and in intact cells, while having no effect on insulin-like growth factor 1 (IGF-1) receptor function. We also reported the binding of this peptide to the insulin receptor beta-subunit in cells, thus providing one of few evidences for synergistic interaction between receptor domains. Our laboratory has recently developed a minigene approach that allows stable expression of a receptor fragment that can specifically modulate insulin receptor functions in cells. In addition, a mutant insulin receptor that lacks this receptor fragment has been constructed and expressed stably in Chinese hamster ovary cells. We plan to examine the effect such mutation will have on insulin receptor-mediated signals, and determine whether introduction of the missing fragment by the minigene approach will restore insulin responsiveness to control levels.