MODULATION OF INSULIN RECEPTOR FUNCTION

工作总结：胰岛素通过胰岛素诱导多效性作用 受体(IR)，其固有的酪氨酸激酶活性是 它的功能。羧基末端结构域是几种结构之一 已在细胞内部分定义的区域 胰岛素受体β-亚基对细胞增殖的作用 胰岛素信号。在这项研究中， 通过稳定表达A基因确定IR的羧基末端结构域 与该受体结构域的1293-1307残基相对应的肽 中国仓鼠卵巢细胞含有大量IR。这个 分析了一些参数对配体介导的反应的影响 细胞，包括受体磷酸化、胸腺嘧啶核苷掺入 DNA、磷脂酰肌醇3‘-激酶活性和丝裂原激活蛋白 激活酶的激活。多肽表达不影响IR 表情。虽然对基本反应的影响很小，但显著的 胰岛素刺激的IR活性和信号转导增强2倍 在几个表达多肽的细胞克隆中观察到的比较 单独转染载体的细胞。在这些试验性的 条件、受体磷酸化和DNA合成 胰岛素样生长因子1没有受到影响。因此，一个离散的 IR羧基末端结构域的非催化区似乎是 参与胰岛素受体信号转导的刺激作用 对胰岛素的反应。重要的是，微型方法代表了一种 一种表达受体胞质结构域的实用方法 调节细胞内的IR功能。

Summary of work: Insulin elicits pleiotropic effects through the insulin receptor (IR), whose intrinsic tyrosine kinase activity is required for its function. The carboxyl-terminal domain is one of several structural regions that has been defined within the intracellular portion of the insulin receptor beta-subunit to contribute to the propagation of the insulin signal. In this study, the functional importance of the carboxyl-terminal domain of IR was ascertained by stable expression of a peptide corresponding to residues 1293-1307 of this receptor domain in Chinese hamster ovary cells harboring large number of IR. The ligand-mediated responses of a number of parameters were analyzed in these cells, including receptor phosphorylation, thymidine incorporation into DNA, phosphatidylinositol 3'-kinase activity and mitogen-activated protein kinase activation. The peptide expression did not influence IR expression. While having minimal effect on basal responses, a significant 2-fold enhancement of insulin-stimulated IR activity and signaling was observed in several peptide-expressing cellular clones when compared to cells transfected with the vector alone. Under these experimental conditions, receptor phosphorylation and DNA synthesis in response to insulin-like growth factor 1 remained unaffected. Thus, a discrete non-catalytic region of the IR carboxyl-terminal domain appears to be involved in the stimulation of insulin receptor signal transduction in response to insulin. Importantly, the minigene approach represents a useful method for expressing receptor cytoplasmic domains that can modulate IR functions in cells.