Biochemical Studies of Worm Insulins

蠕虫胰岛素的生化研究

• 批准号: 6802446
• 负责人: MICHAEL Aaron WEISS
• 金额: $ 27.37万
• 依托单位: CASE WESTERN RESERVE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-09-20 至 2007-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6802446
• 关键词: Caenorhabditis elegans; X ray crystallography; analytical ultracentrifugation; binding proteins; biochemistry; helminth genetics; insulin; insulin receptor; insulinlike growth factor; nuclear magnetic resonance spectroscopy; peptide chemical synthesis; polymerase chain reaction; protein structure function; protein tyrosine kinase; receptor binding; recombinant proteins; site directed mutagenesis

DESCRIPTION (provided by applicant): An insulin-related signaling pathway in the nematode Caenorhabditis elegans controls aging and life span. Remarkably, the C. elegans genome contains 38 putative insulin-like genes and a single orthologue of the human insulin receptor (designated daf-2). Do nematode insulin-like proteins truly resemble mammalian insulins in structure and function? Why are there such a diversity of ligands? We propose to synthesize representative insulin-like polypeptides (INS proteins) and investigate their structures and receptor-binding properties. The proposed studies will illuminate the evolution of the insulin structure and dissect a signaling pathway in a genetic model of senescence. The proposed studies focus on four questions. (1) Given their sequence divergence, are INS proteins truly members of the insulin superfamily, and if so, how are the divergent side chains accommodated within a conserved architecture? (2) Does DAF-2 function as a receptor tyrosine kinase, and if so, is its kinase activity positively or negatively regulated by INS ligands? (3) Do INS proteins bind to the human insulin receptor, and if so, how can their seemingly divergent surfaces mimic human insulin? (4) Conversely, does human insulin bind to and regulate DAF-2? A long-term collaboration is proposed with Prof. Guy G. Dodson to compare co-crystal structures of hormone-receptor complexes. Preliminary studies of a representative INS protein have established that -- despite an overall insulin-like fold -- its putative receptor-binding surface differs dramatically from that of human insulin. As a seeming paradox, the protein nonetheless binds to and activates the human insulin receptor. Human insulin likewise binds to the DAF-2 receptor. Novel INS ligands may provide an unexpected starting point for design of human insulin agonists. Given the growing importance of insulin analogs to optimize treatment of diabetes mellitus and the possible clinical utility of IGF-I antagonists in cancer therapy, studies of the INS family may have translational implications in therapeutic protein design.

描述（由申请人提供）： 线虫中的胰岛素相关信号通路控制衰老和寿命。值得注意的是，C.线虫基因组含有38个推定的胰岛素样基因和人胰岛素受体的单一直向同源物（命名为DAF-2）。线虫胰岛素样蛋白在结构和功能上真的与哺乳动物胰岛素相似吗？为什么会有如此多样的配体？我们建议合成代表性的胰岛素样多肽（INS蛋白），并研究其结构和受体结合特性。拟议的研究将阐明胰岛素结构的演变，并剖析衰老遗传模型中的信号通路。 建议的研究集中在四个问题。(1)考虑到它们的序列差异，INS蛋白质真的是胰岛素超家族的成员吗？如果是的话，不同的侧链是如何容纳在一个保守的结构中的？(2)INS-2是否作为受体酪氨酸激酶发挥作用？如果是，其激酶活性是否受INS配体的正或负调节？(3)INS蛋白质与人胰岛素受体结合吗？如果是这样，它们看似不同的表面是如何模仿人胰岛素的？(4)相反，人胰岛素是否与β 2结合并调节β 2？建议与Guy G教授进行长期合作。Dodson比较了受体-受体复合物的共晶体结构。对代表性INS蛋白的初步研究已经确定，尽管总体上具有胰岛素样折叠，但其推定的受体结合表面与人胰岛素的受体结合表面显著不同。作为一个看似矛盾的，蛋白质仍然结合并激活人类胰岛素受体。人胰岛素同样与β 2受体结合。新型INS配体可能为设计人胰岛素激动剂提供意想不到的起点。鉴于胰岛素类似物对优化糖尿病治疗的重要性日益增加，以及IGF-I拮抗剂在癌症治疗中的可能临床用途，INS家族的研究可能在治疗性蛋白质设计中具有翻译意义。