G PROTEINS AND PHOSPHOLIPASE C REGULATION IN RPE CELLS

鸟嘌呤核苷酸调节蛋白(G蛋白)是一类 受体介导的调节所需的同源多肽 视网膜cGMP磷酸二酯酶、腺苷酸环化酶、磷脂酶C和 A2、K+和Ca~(2+)离子通道亚群。这些信号转导 分子也参与了细胞调节的基本过程 在高度专门化的细胞功能中，如光传导和 嗅觉。 对特定的G蛋白和G蛋白的分子生物学知之甚少。 视网膜色素上皮(RPE)细胞的信号转导。RPE是一种 高度特化的单层细胞，具有密切的功能关系 有光感受器。RPE的多种功能，如果受到干扰，可以 导致各种视力障碍，包括浆液性视网膜脱离 和视网膜退化。在增殖性玻璃体视网膜病变中，RPE细胞 被认为经历了异常的趋化、迁移和增殖。一个 这一理论的假设是吞噬RPE的重要行为 细胞，如趋化、转化和增殖，涉及 G蛋白和磷脂酶C的调节，因为这些 信号转导分子是调节类似物的基础 在巨噬细胞、中性粒细胞、 和其他类型的细胞。这项研究的长期目标是确定 肌醇磷脂对磷脂酶C调节的分子基础 RPE GTP结合蛋白和开发相互作用的特定试剂 通过这些信号转导分子来改变细胞的反应。 为了实现这个项目的目标，来自牛和人的RPE细胞 组织将通过既定的方法进行培养。在这些培养的细胞中， 化学诱导剂和生长因子对磷脂酶C的调节 将被研究，并将分析RPE G蛋白的表达 分子遗传学。此外，一个人RPE cDNA文库将被 从均质细胞培养构建用于小说鉴定的 RPE中G蛋白基因产物。G蛋白拮抗剂的作用，如 作为百日咳毒素、合成肽和抑制性抗体 将测定磷脂酶C和RPE细胞的反应。这项工作可能会 为合理开发符合以下条件的试剂或药物提供依据 与特定的G蛋白和其他信号转导分子相互作用 RPE。

Guanine nucleotide regulatory proteins (G proteins) are a family of homologous polypeptides that are required for receptor-mediated regulation of retinal cGMP phosphodiesterase, adenylyl cyclase, phospholipases C and A2, and subsets of K+ and Ca2+ ion channels. These signal-transducing molecules are involved in fundamental processes of cell modulation, as well as in highly specialized cell function, such as phototransduction and olfaction. Little is known about specific G proteins and the molecular biology of signal transduction in retinal pigment epithelial (RPE) cells. The RPE is a highly specialized monolayer of cells with a close functional relationship with photoreceptors. The multiple functions of the RPE, if disturbed, may lead to a variety of visual disorders, including serous retinal detachment and retinal degeneration. In proliferative vitreoretinopathy, RPE cells are believed to undergo abnormal chemotaxis, migration, and proliferation. A hypothesis of this proposal is that important behaviors of phagocytic RPE cells, such as chemotaxis, transformation, and proliferation, involve regulation by G proteins and phosphoinositide phospholipase C, since these signal-transducing molecules are the basis for the regulation of similar activities that have been studied intensively in macrophages, neutrophils, and other cell types. The long-term goal of this study is to determine the molecular basis for the regulation of phosphoinositide phospholipase C by RPE GTP-binding proteins and to develop specific reagents that interact with these signal-transducing molecules to modify cell response. To achieve the goals of this project, RPE cells from bovine and human tissue will be cultured by established methods. In these cultured cells, the regulation of phospholipase C by chemoattractants and growth factors will be studied, and the expression of RPE G proteins will be analyzed by molecular genetics. In addition, a human RPE cDNA library will be constructed from homogeneous cell cultures for the identification of novel G protein gene products in RPE. The effects of G protein antagonists, such as pertussis toxin, synthetic peptides, and inhibitory antibodies, on phospholipase C and RPE cell responses will be determined. This work may provide a basis for the rational development of reagents or drugs that interact with specific G proteins and other signal-transducing molecules in RPE.