SEMISYNTHETIC IGF-I/INSULIN HYBRIDS AS RECEPTOR PROBES

半合成 IGF-I/胰岛素杂交体作为受体探针

• 批准号: 2143174
• 负责人: DONALD F STEINER
• 金额: $ 19.74万
• 依托单位: UNIVERSITY OF CHICAGO
• 依托单位国家: 美国
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-02-01 至 1997-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2143174
• 关键词: affinity labeling; chimeric proteins; fibroblasts; human tissue; insulin; insulin receptor; insulinlike growth factor; peptide chemical synthesis; peptide hormone analog; protein structure function; radiotracer; receptor binding; tissue /cell culture

This proposal has long-term goals related to (a) identifying the structural attributes of insulin-like growth factor I (IGF-I) which determine its potency for interactions with type I IGF receptors, and its consequent overall biological effects, (b) evaluating the development of rules that might apply to the separate determinants of affinity and selectivity for receptor interactions within structurally related groups of ligands and receptors, and (c) considering the potential for development of IGF-I analogs that might be of therapeutic or experimental value. Specific aims for the project are summarized as follows: (a) To prepare hybrid IGF-I/insulin analogs with selected structural changes and amino acid replacements by chemical peptide synthesis and semisynthesis. (b) To evaluate the potencies of these analogs with regard to their abilities to bind to the type I IGF and insulin receptors through binding competition studies and direct analysis of radiolabeled ligand binding. (c) To consider the separate issues of receptor site affinity and selectivity in relation to the IGF-I and insulin systems through comparisons of analog interactions with both receptors. (d) To address aspects of potential differences in the solution structures of analogs by spectroscopic methods and chemical modification. (e) To evaluate the consequences of structural changes in these analogs in relation to their biological activities in vitro, by use of assays for 3H-thymidine incorporation into DNA and for additional metabolic responses. (f) To evaluate the potential biological implications of binding site heterogeneity in ligand interactions with the type I IGF receptor through the kinetic analysis of related binding studies. (g) To approach an understanding of type I IGF receptor heterogeneity at the molecular level through use of chemical and affinity methods. As aberrations in IGF-I physiology can be expected to result under different sets of circumstances in either inappropriately low or inappropriately high rates of tissue growth, and as the IGF-I system could be useful in by-passing the insulin system in states of insulin resistance, it is not difficult to envision the potential health-related importance of analogs of IGF-I that might (a) be selective for one or the other of its actions, (b) be even more potent than the natural hormone, (c) inhibit the action endogenous hormone by binding to receptor without inducing cellular responses, or (d) act through multiple receptor systems to produce desired metabolic effects. This proposal represents a study of the IGF-I system at a fundamental level, at this stage, and the application of the methods of chemical peptide synthesis and semisynthesis to the elucidation of relevant structure-function relationships.

该提案的长期目标涉及 (a) 确定 胰岛素样生长因子 I (IGF-I) 的结构属性 确定其与 I 型 IGF 受体相互作用的效力，及其 随之而来的总体生物效应，(b) 评估 可能适用于亲和力和亲和力的单独决定因素的规则 结构相关基团内受体相互作用的选择性 配体和受体，以及（c）考虑开发潜力 可能具有治疗或实验价值的 IGF-I 类似物。 该项目的具体目标概述如下： (a) 制备具有选定结构变化的混合 IGF-I/胰岛素类似物，并 通过化学肽合成和半合成进行氨基酸替代。 (b) 评估这些类似物的功效 通过结合与 I 型 IGF 和胰岛素受体结合的能力 放射性标记配体结合的竞争研究和直接分析。 (三) 考虑受体位点亲和力和选择性的单独问题 通过类似物的比较，了解 IGF-I 和胰岛素系统的关系 与两种受体的相互作用。 (d) 解决潜在问题的各个方面 通过光谱方法测定类似物溶液结构的差异 和化学改性。 (e) 评估结构性后果 这些类似物的变化与其生物活性有关 体外，通过使用 3H-胸苷掺入 DNA 的测定法和 额外的代谢反应。 (f) 评估潜在的生物 结合位点异质性对配体相互作用的影响 通过相关结合动力学分析I型IGF受体 研究。 (g) 了解 I 型 IGF 受体 通过使用化学和亲和力在分子水平上实现异质性 方法。 由于 IGF-I 生理学异常可能会导致 在不同的情况下，无论是不适当的低还是 不适当的高组织生长率，并且 IGF-I 系统可以 在胰岛素抵抗状态下有助于绕过胰岛素系统， 不难预见与健康相关的潜在重要性 IGF-I 的类似物可能 (a) 对它的一个或另一个具有选择性 作用，(b) 比天然激素更有效，(c) 抑制 通过与受体结合来作用内源激素，而不诱导细胞 反应，或（d）通过多个受体系统产生所需的 代谢影响。 该提案代表了对 IGF-I 系统的研究 在此阶段，基础水平以及方法的应用 化学肽合成和半合成以阐明相关 结构-功能关系。