Glycosaminoglycans in FGF/FGFR Signaling.

FGF/FGFR 信号转导中的糖胺聚糖。

• 批准号: 6837149
• 负责人: LIJUAN ZHANG
• 金额: $ 30.6万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-01-01 至 2008-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6837149
• 关键词: CHO cells; biological signal transduction; carbohydrate biosynthesis; carbohydrate sequence; carbohydrate structure; chondroitin sulfates; enzyme activity; fibroblast growth factor; growth factor receptors; heparan sulfate; isomerase; mass spectrometry; molecular cloning; mucopolysaccharides; protein purification

DESCRIPTION (provided by applicant): Fibroblast growth factor (FGF) signaling is contingent on the formation of a ternary complex with the FGF receptor (FGFR) and with specific structures of glycosaminoglycan (GAG) chains. Genetic defects in FGFs, FGFRs or in GAG biosynthesis have been shown to be lethal or result in overgrowth, dwarfism, and other syndromes. Animals with defects in GAG biosynthesis show a complete loss of FGF/FGFR signaling pathways. We recently discovered that chondroitin sulfate could activate FGF/FGFR signaling in a fashion similar to heparan sulfate. Both heparan sulfate and chondroitin sulfate are highly sulfated linear GAG chains abundantly expressed on the cell surface and in the extracellular matrix in the forms of heparan sulfate, chondroitin sulfate, or heparan/chondroitin sulfate hybrid proteoglycans. The FGF/FGFR/GAG interactions depend to a large extent on the specific GAG sequences. GAG sequences are not directly encoded by genes, but are put together in the Golgi by enzymes encoded by over 40 genes. This generates a huge variety of GAG sequences. The overall goal of the current grant proposal is to understand how GAGs coordinately regulate FGF/FGFR signaling at the molecular level. In the first aim, we will dissect the roles of heparan and chondroitin sulfate in FGF/FGFR signaling in a defined cellular system, The central hypothesis of this aim is that specific heparan and chondroitin sulfate sequences regulate distinct aspects of FGF/FGFR signaling. Since most animal cells make both heparan and chondroitin sulfate, our goal is to prepare a comprehensive library of CHO cell lines that express defined heparan or chondroitin sulfate sequences. This library will be a unique tool for establishing GAG structure-function relationships in FGF/FGFR signaling. In the second aim, we will clone the long sought epimerase of chondroitin sulfate biosynthesis and use it as a tool to rebuild chondroitin sulfate structures that activate FGF/FGFR signaling. In the third aim, we will determine by mass spectrometry the fine structures of GAGs in growth plates that are involved in FGF/FGFR signaling. The central hypothesis of this aim is that specific heparan and chondroitin sulfate structures function to enhance or suppress FGF signals at different biological sites within the growth plate. The goal of this aim is to discover such GAG structures. The long-term outcome of this work will contribute to a better understanding of diseases caused by disordered GAG-dependant FGF/FGFR signaling. The work may suggest novel therapeutic applications of GAG biology.

描述（由申请人提供）：成纤维细胞生长因子（FGF）信号传导取决于与FGF受体（FGFR）和糖胺聚糖（GAG）链的特定结构形成的三元复合物。FGFs、fgfr或GAG生物合成中的遗传缺陷已被证明是致命的，或导致过度生长、侏儒症和其他综合征。具有GAG生物合成缺陷的动物表现为FGF/FGFR信号通路的完全丧失。我们最近发现硫酸软骨素可以以类似硫酸肝素的方式激活FGF/FGFR信号。硫酸肝素和硫酸软骨素都是高度硫酸化的线性GAG链，在细胞表面和细胞外基质中以硫酸肝素、硫酸软骨素或硫酸肝素/硫酸软骨素杂交蛋白聚糖的形式大量表达。FGF/FGFR/GAG相互作用在很大程度上取决于特定的GAG序列。GAG序列不是由基因直接编码的，而是由40多个基因编码的酶在高尔基体中合成的。这就产生了种类繁多的GAG序列。当前拨款提案的总体目标是了解GAGs如何在分子水平上协调调节FGF/FGFR信号传导。在第一个目标中，我们将剖析肝素和硫酸软骨素在特定细胞系统中FGF/FGFR信号传导中的作用，该目标的中心假设是特定的肝素和硫酸软骨素序列调节FGF/FGFR信号传导的不同方面。由于大多数动物细胞同时产生肝素和硫酸软骨素，我们的目标是制备一个表达明确的肝素或硫酸软骨素序列的CHO细胞系的综合文库。该文库将成为建立FGF/FGFR信号中GAG结构-功能关系的独特工具。在第二个目标中，我们将克隆长期寻找的硫酸软骨素生物合成的外甲酰基酶，并将其用作重建激活FGF/FGFR信号的硫酸软骨素结构的工具。在第三个目标中，我们将通过质谱法确定生长板中参与FGF/FGFR信号传导的gag的精细结构。这一目标的中心假设是，特定的肝素和硫酸软骨素结构可以增强或抑制生长板内不同生物位点的FGF信号。这个目的的目标是发现这样的GAG结构。这项工作的长期结果将有助于更好地理解由gag依赖性FGF/FGFR信号紊乱引起的疾病。这项工作可能为GAG生物学提供新的治疗应用。