STRUCTURE AND FUNCTION OF THE LIVER RECEPTOR OF CS PROTEIN

该项目的广泛的长期目标是确定 肝细胞与疟疾相互作用的机制 子孢子，并开发特定的抑制剂，防止关键的 疾病的肝脏阶段。 具体目标是描述 来自肝细胞的硫酸乙酰肝素蛋白聚糖（HSPG），其结合至 疟疾环子孢子蛋白（CS）通过1）定义寡糖 其识别CS蛋白的配体区域II+， 2)表征蛋白质核心，3）在电子上证明 显微镜下观察CS结合HSPG的形态; 在细胞水平上，HSPG与HSPG之间相互作用的结果是， 和CS，特别是，是否存在CS量化和信号 转导 对CS区域II+具有亲合力的硫酸乙酰肝素寡糖将 分离、解聚并通过HPLC表征其结构。 核心蛋白的定义包括确定其在SDS中的Mr。 PAGE，其与细胞表面的各种单克隆抗体的反应性 HSPGs的表达及相应基因的克隆。 我们将研究营业额 HepG 2细胞的细胞表面HSPGs在CS不存在下，然后 确定CS和HSPG受体的命运， 互动 为此目的，将用[35 S]-[35 S] 硫酸盐和用125 I]-放射性标记的CS（或区域II-加肽）。 碘。 CS后HepG 2细胞磷酸化模式的变化，或 区域II+肽结合将通过磷酸氨基酸 分析，并通过抗体磷酸酪氨酸。 小寡糖（或模拟物），结合区域II+并抑制 子孢子附着在肝细胞上可能具有医学应用， 预防疟疾感染，此外， 研究显示II+区的宿主蛋白的功能 基序，如血小板反应蛋白、备解素、末端补体 成分和F-spondin，一种参与发育的分子， 神经系统

The broad, long-term objectives of this project are to define the mechanisms involved in the interaction between hepatocytes and malaria sporozoites and to develop specific inhibitors that prevent the crucial hepatic stage of the disease. The specific aims are to characterize the heparan sulfate proteoglycans (HSPG) from hepatocytes which bind to the malaria circumsporozoite protein (CS) by 1) defining the oligosaccharide which recognizes the ligand region II-plus of the CS protein, 2)characterizing athe core protein, 3) demonstrating at the electron microscopical level the morphology of the CS-binding HSPG, and 4) examining at the cellular level the consequences of the interaction between the HSPG and CS, in particular, whether there is CS interiorization and signal transduction. Heparan sulfate oligosaccharides with avidity to the CS region II-plus will be isolated, depolymerized an their structure characterized by HPLC. Definition of the core protein includes the determination of its Mr in SDS- PAGE, of its reactivity with various monoclonal antibodies to cell surface HSPGs, and cloning of the corresponding gene. We will study the turnover of the cell surface HSPGs of HepG2 cells in the absence of CS, and then determine the fate of CS and of the HSPG receptors following their interaction. For this purpose, the HSPGs will be radiolabeled with [35S]- sulfate, and the CS (or region II-plus peptides) radiolabeled with 125I]- iodine. Changes in the phosphorylation patterns of HepG2 cells upon CS, or region II-plus peptide binding will be examined by phosphoamino acid analysis, and by means of antibodies to phosphotyrosine. Small oligosaccharides (or mimics) which bind to region II-plus and inhibit attachment of sporozoites to hepatocytes may have medical applications in the prophylaxis of malaria infection, and in addition may be valuable tools to study the function of host proteins which display the region II-plus motif, such as thrombospondin, properdin, the terminal complement components and F-spondin, a molecule involved in the development of the nervous system.