PC-1 and Insulin Receptor Signaling

描述：（从申请人的描述扫描）胰岛素抵抗 是I型和II型糖尿病患者的特征。我们事先 研究表明胰岛素抗性， 胰岛素受体（IR）酪氨酸激酶活性降低， 膜糖蛋白PC-1的含量。PC-1是H类外蛋白， 磷酸二酯酶活性的生理功能还不清楚， 并且受生长因子、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α亚基之间的连接域， 配体结合结构域和β亚基酪氨酸激酶结构域。我们有 发现将PC-1转染并过表达到培养的细胞中， 选择性降低IR酪氨酸激酶活性和JR信号传导。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剂 和2，以进一步了解PC-1如何影响IR信号。我们建议 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，我们将研究 PC-1对胰岛素敏感细胞：小鼠3 T3 L1脂肪细胞和大鼠的作用 L 6肌细胞。第三，我们将研究导致PC-1的机制。 过度表达利用胰岛素抵抗的成纤维细胞和肌肉细胞 患者，我们将确定是否过度表达是由转录 或转录后机制。第四，我们有数据。在体外和 体内，表明PC-1直接与IR α亚基相互作用。我们 将研究PC-1与IR的相互作用， 其中PC-1与JR结合。为此，我们将使用直接绑定 问题研究此外，将产生IR和PC-1的突变体， 定位蛋白质相互作用的离散位点。这一系列的研究 因此，应就PC-1在以下方面作用提供重要的新信息： 胰岛素抵抗及PC-1抑制胰岛素抵抗的分子机制 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.