MECHANISMS OF FGF RECEPTOR REGULATION AND SIGNALING

描述(摘自申请者摘要)：成纤维细胞生长因子 (FGFs)包括至少18个结构上相关的多肽家族，这些多肽 在胚胎发育、血管生成和伤口愈合中发挥重要作用。 FGFs通过结合和激活不同的 受体酪氨酸激酶的亚类。哺乳动物成纤维细胞生长因子受体家族 由四个基因(FGFR1-FGFR4)组成。每个FGFR都绑定了一个独特的曲目 成纤维细胞生长因子配体。这种结合的特异性是由 胞外区的一级结构以及选择性剪接。 二聚化对于FGFR的激活是必不可少的，然而，仅有FGFs是不能的 诱导受体二聚化和激活，需要类肝素 分子来促进这一过程。调查人员提出了四个具体的建议 目的：研究FGFs和肝素的分子机制 含有硫酸盐的蛋白多糖诱导受体二聚化和激活， 赋予配体结合专一性的结构要求，以及 胞外区各亚区对细胞外信号调节的作用 配基结合。此外，在人类中发现的FGFR突变的影响 将检查与配体结合有关的骨骼疾病。这些目标将是 通过x射线结晶学研究和生物化学相结合完成 利用培养的细胞表达突变的FGFRs的实验。此外， FGFs、肝素及其配体结合域的缔合热力学 FGFRs将通过等温滴定量热法和Biacore进行表征 分析。这些研究将增加我们对FGFR信号转导的了解 并为理解FGFR突变导致的影响提供了基础 在人类骨骼疾病中。由于FGFs参与了血管生成和 肿瘤的发生，预计这些结构和结果 功能分析有助于新型成纤维细胞生长因子的合理设计 对于治疗癌症的拮抗剂以及增进我们对 其他肝素结合生长因子

DESCRIPTION (Adapted from applicant's abstract): The fibroblast growth factors (FGFs) comprise a family of at least 18 structurally related polypeptides that play important roles in embryonic development, angiogenesis and wound healing. FGFs exert these diverse effects by binding to and activating a distinct subclass of receptor tyrosine kinases. The mammalian FGF receptor (FGFR) family is composed of four genes (FGFR1-FGFR4). Each FGFR binds a unique repertoire of FGF ligands. The specificity of this binding is determined by differences in primary structure in the extracellular domain as well as alternative splicing. Dimerization is essential for FGFR activation, however, FGFs alone are unable to induce receptor dimerization and activation, requiring heparin-like molecules to facilitate this process. The investigator proposes four specific aims to investigate the molecular mechanisms by which FGFs and heparin sulfate-containing proteoglycans induce receptor dimerization and activation, the structural requirements that impart ligand binding specificity, and the contribution of each subdomain of the extracellular domain to regulation of ligand binding. In addition, the effects of FGFR mutations found in human skeletal disorders on ligand binding will be examined. These aims will be accomplished by x-ray crystallographic studies combined with biochemical experiments employing cultured cells expressing mutant FGFRs. In addition, the association thermodynamics of FGFs, heparin and the ligand-binding domains of FGFRs will be characterized by isothermal titration calorimetry and BIAcore analysis. These studies will increase our knowledge of FGFR signal transduction and provide a basis for understanding the effects of FGFR mutations that result in human skeletal disorders. Since FGFs are involved in angiogenesis and tumorigenesis, it is anticipated that the results of these structural and functional analyses will facilitate the rational design of novel FGF antagonists for the treatment of cancer as well as enhance our understanding of other heparin-binding growth factors