ROLE OF PROTEIN INTERACTIONS IN RETINA DEVELOPMENT AND FUNCTION

蛋白质相互作用在视网膜发育和功能中的作用

• 批准号: 6290136
• 负责人: SOFIA P BECERRA
• 金额: --
• 依托单位: NATIONAL EYE INSTITUTE
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6290136
• 关键词: X ray crystallography; gene deletion mutation; growth factor; membrane proteins; molecular cloning; protein structure function; retina; retinal pigment epithelium; tissue /cell culture

Work in this research group is aimed at elucidating the mechanism of action of pigment epithelium-derived factor (PEDF). PEDF, an extracellular glycoprotein of the interphotoreceptor matrix, vitreous and aqueous, has interesting neurotrophic activities. It promotes neuronal differentiation of retinoblastoma cells, the survival of cerebellar granule cells, neurite-outgrowth and survival of developing spinal motor neurons. It can delay the death of photoreceptors in mouse models of inherited retinal degenerations. By sequence homology, PEDF is included in the serpin superfamily, but it has no known inhibitory activity against serine proteases. Using classical radioligand binding assays, we showed that retinoblastoma and cerebellar granule cells have high-affinity cell-surface receptors for PEDF. A biologically active peptide derived from PEDF spanning positions 44-121, 44-mer, is a competitor of the full length PEDF for the binding to cell-surface receptors, and represents the receptor binding region of PEDF. PEDF also binds to high- affinity receptors on membranes of bovine neural retina. Peptide 44-mer competes for this binding with similar kinetics as that of unlabeled PEDF, while cytochrome c, a control protein, does not. We continued the studies on the interactions of PEDF with components of extracellular matrixes. PEDF binds specifically to hyaluronan, a major glycosaminoglycan component of the interphotoreceptor matrix and vitreous. This binding is mediated via ionic interactions. Heparin and heparan sulfate are natural glycosaminoglycans secreted by retinoblastoma cells to the media. Binding of PEDF to retinoblastoma cell membranes increases when supplemented with conditioned media. Removal of heparan sulfates from cell cultures decreases the binding of PEDF to the cell-surface receptors on retinoblastoma cells. - neurotrophic factor, serpin, receptor-binding, glycosaminoglycan, human retinoblastoma cells, bovine retina, retinal degenerations

该研究小组的工作旨在阐明色素上皮衍生因子（PEDF）的作用机理。 PEDF是玻璃体和水性基质的细胞外糖蛋白具有有趣的神经营养活性。它促进了视网膜细胞细胞的神经元分化，小脑颗粒细胞的存活，神经突出产生和发育中的脊髓运动神经元的存活。它可以延迟遗传性视网膜变性小鼠模型中光感受器的死亡。按序列同源性，PEDF被包括在Serpin超家族中，但没有对丝氨酸蛋白酶的抑制活性。使用经典的放射性结合测定法，我们表明视网膜细胞瘤和小脑颗粒细胞具有高亲和力细胞表面受体的PEDF受体。从PEDF跨越位置衍生的生物活性肽44-121，44-mer是与细胞表面受体结合的全长PEDF的竞争者，代表PEDF的受体结合区域。 PEDF还与牛神经视网膜膜上的高亲和力受体结合。肽44-mer的竞争与未标记的PEDF相似的动力学竞争，而对照蛋白的细胞色素C则没有。我们继续研究PEDF与细胞外基质组成部分的相互作用。 PEDF专门结合透明质酸，透明质酸是透明体基质和玻璃体的主要糖胺聚糖成分。这种结合是通过离子相互作用介导的。肝素和硫酸乙酰肝素是视网膜细胞细胞分泌到培养基的天然糖胺聚糖。补充条件培养基时，PEDF与视网膜母细胞瘤细胞膜的结合增加。从细胞培养物中去除乙par硫酸盐会降低PEDF与视网膜细胞瘤细胞上细胞表面受体的结合。 - 神经营养因子，SERPIN，受体结合，糖胺聚糖，人视网膜细胞细胞，牛视网膜，视网膜变性