PC-1 and Insulin Receptor Signaling

描述：(摘自申请者的描述)对胰岛素的抵抗 是I型和II型糖尿病患者的一个特征。我们的前辈 研究表明，胰岛素抵抗、 降低胰岛素受体(IR)酪氨酸激酶活性，并增加 膜糖蛋白PC-1的含量。PC-1是一种H类外源蛋白，具有 生理功能尚不清楚的磷酸二酯酶活性， 并受生长因子、细胞因子和糖皮质激素的控制。 PC-1与JR的α亚基在残基之间的区域相互作用 485-599。该区域作为阿尔法亚基之间的连接域 配体结合域和β亚单位酪氨酸激酶域。我们有 PC-1基因在培养细胞中的转染和过表达 分别降低IR酪氨酸激酶活性和JR信号转导。我们 因此，假设PC-1在胰岛素抵抗中起作用。我们现在 计划进一步证明PC-1是胰岛素作用的重要调节器 2进一步了解PC-1对IR信令的影响。我们建议 如下：首先，我们将在转基因小鼠中过表达PC-1，以确定 在这个物种中，PC-1是否会导致胰岛素抵抗。第二，我们会研究 PC-1对小鼠3T3 L1脂肪细胞和大鼠胰岛素敏感细胞的影响 L6肌细胞。第三，我们将调查导致PC-1的机制 过度表达。使用胰岛素抵抗患者的成纤维细胞和肌肉细胞 患者，我们将确定过度表达是否由转录引起 或转录后机制。第四，我们有数据。在体外和体内 Vivo，表明PC-1与IRα亚基直接相互作用。我们 我将通过阐明PC-1与IR的相互作用 其中PC-1绑定到JR。为此，我们将使用直接绑定 学习。此外，IR和PC-1的突变体将被生产出来 确定蛋白质-蛋白质相互作用的离散位置。这一系列研究 因此，应该提供重要的新信息，关于PC-1在 胰岛素抵抗与PC-1抑制IR的分子机制 功能。

DESCRIPTION: (Scanned from the applicant's description) Resistance to insulin is a feature of patients with Type I and Type II diabetes mellitus. Our prior studies have shown that correlations exist between insulin resistance, decreased insulin receptor (IR) tyrosine kinase activity, and an increased content of membrane glycoprotein PC-1. PC-1 is a class H exoprotein with phosphodiesterase activity whose physiological function is not well understood, and is under the control of growth factors, cytokines, and glucocorticoids. PC-1interacts with the alpha subunit of the JR in a region between residues 485-599. This region serves as a connecting domain between the alpha subunit ligand binding domain and the beta subunit tyrosine kinase domain. We have found that transfection and overexpression of PC-1 into cultured cells se1ectively reduces both IR tyrosine kinase activity and JR signaling. We hypothesize, therefore, that PC-1 plays a role in insulin resistance. We now plan to document further that PC-1 is an important regulator of insulin action and 2 to further understand how PC-1 influences IR signaling. We propose the following: First, we will overexpress PC-1 in transgenic mice to determine whether in this species PC-1 causes insulin resistance. Second, We will study the effect of PC-1 on insulin sensitive cells: mouse 3T3 L1 adipocytes and rat L6 muscle cells. Third, we will investigate the mechanisms that cause PC-1 overexpression. Employing fibroblasts and muscle cells from insulin resistant patients, we will determine whether overexpression is caused by transcriptional or post-transcriptional mechanisms. Fourth, we have data. both in vitro and in vivo, indicating that PC-1 directly interacts with the IR alpha subunit. We will investigate the interactions of PC-1 with the IR by elucidating how and where PC-1 binds to the JR. For this purpose, we will employ direct binding studies. In addition, mutants of both the IR and PC-1 will be produced to locate discrete sites of protein-protein interaction. These series of studies should provide important new information, therefore, as to role of PC-1 in insulin resistance and the molecular mechanisms whereby PC-1 inhibits IR function.