Regulation of insulin-like growth factor I receptor tyrosine kinase

描述(申请人提供)：本项目重点研究调节胰岛素样生长因子I受体(IGF1R)的分子机制。许多酪氨酸激酶的组成性或不适当的激活在各种形式的人类癌症的进展和发展中起着作用。最近的证据表明IGF1R与恶性转化有关，IGF1R已成为抗癌药物设计的靶点。到目前为止，还没有开发出临床上有效的IGF1R抑制剂。 目的1研究胰岛素样生长因子1R(IGF1R)自身磷酸化的机制。在与配体结合后，IGF1R通过激活环的三个位置的磷酸化而被激活。我们将使用生化、生物物理和计算方法来确定每个磷酸化的功能意义。 目的2：最近，我们与Stevan Hubbard博士合作，确定了IGF1R的一个二聚体结构，它可能代表着自动磷酸化过程中的一个中间体。我们将进行生化和细胞生物学实验来测试这种可能性。这种二聚体结构也可以解释在两名非胰岛素依赖型糖尿病患者中观察到的胰岛素受体Arg-to-Gln突变的影响。 目的3探讨IGF1R膜旁区域参与自身抑制的假说。我们将研究IGF1R缺陷小鼠来源的成纤维细胞的膜旁突变。我们还将使用生化和结构方法对纯化的蛋白质进行分析。

DESCRIPTION (provided by applicant): This project focuses on the molecular mechanisms that regulate the insulin-like growth factor I receptor (IGF1R). Constitutive or inappropriate activation of many tyrosine kinases plays a role in the progression and development of various forms of human cancer. Recent evidence has implicated IGF1R in malignant transformation, and IGF1R has emerged as a target for anticancer drug design. No clinically effective inhibitors for IGF1R have been developed to date. Aim 1 studies the mechanism of IGF1R autophosphorylation. Upon ligand binding, IGF1R is activated by phosphorylation at three sites in the activation loop of the kinase catalytic domain. We will determine the functional significance of each phosphorylation using biochemical, biophysical, and computational approaches. Aim 2: In collaboration with Dr. Stevan Hubbard, we recently determined a dimeric structure of IGF1R which potentially represents an intermediate in the autophosphorylation process. We will carry out biochemical and cell biology experiments to test this possibility. The dimeric structure may also explain the effect of an Arg-to-Gln mutation in insulin receptor observed in two patients with non-insulin- dependent diabetes. Aim 3 will explore the hypothesis that the juxtamembrane region of IGF1R is involved in autoinhibition. We will study juxtamembrane mutants in fibroblasts derived from IGF1R-deficient mice. We will also analyze the purified proteins using biochemical and structural approaches.