MEMBRANE-ASSOCIATED GUANYLATE KINASE HOMOLOGS

通过四个实验室的合作和个人努力，我们 提议对一个新的机构的职能进行协调分析 已发现的名为MAGUKs(膜相关鸟酸盐)的蛋白质家族 激酶同源物)似乎具有重要结构和信号 在无脊椎动物和脊椎动物的细胞膜上的作用。这些 蛋白质都含有一个与鸟苷酸激酶(GUK)同源的结构域，一个 SH3结构域和一个或三个附加的同源结构域(DHR) 其功能尚不清楚。在项目1中，分子遗传学方法 将用于调查Maguk DlgA，它是 果蝇的隔膜连接，是维持隔膜所必需的 连接结构、细胞形状、极性和增殖控制。在……里面 项目2，将使用生化方法来识别 与MAGUK相互作用，绘制结合位点图，并研究如何 与其他蛋白质的结合会影响功能。该项目将重点放在 P55，它是从人红细胞膜中鉴定出来的，Hdlg， 它是从淋巴细胞中鉴定出来的；这两种蛋白质都被证明是 结合到将细胞骨架连接到膜上的其他蛋白质上，并 稳定细胞形状。项目#3涉及可能的信令 哺乳动物紧密连接中Z0-1和Z0-2、MAGUKs的功能 维持组织结构、跨上皮通透性所必需的 障碍物和细胞极性。项目4将是一个分子遗传学 新城疫衣原体Maguk lin-2的结构分析 与钙/钙调蛋白依赖同源的附加N末端结构域 项目#1还包括对蛋白激酶的遗传分析。 相应的果蝇基因。使用分子、基因的组合 和细胞生物学的方法，我们将确定 MAGUK负责控制它们的亚细胞定位， 与它们相关的蛋白质，以及它们如何与已知信号相互作用 转导通路。生化分析将被用来确定 GUK结构域的催化和/或调节作用，并测试 这些蛋白质作为酪氨酸激酶的底物。参赛者 实验室将把实验系统与独特的 优势，他们将贡献生物化学、遗传学方面的专业知识 和细胞生物学，来定义一个非凡的新家族的功能 在细胞结构控制中起重要作用的蛋白质， 分化和增殖。

Through the collaborative and individual efforts of four laboratories we propose to carry out a coordinated analysis of the functions of a newly discovered family of proteins named MAGUKs (Membrane-Associated GUanylate Kinase Homologs) that appear to have important structural and signalling roles at the cell membrane in both invertebrates and vertebrates. These proteins all contain a domain with homology to guanylate kinase (GUK), an SH3 domain and one or three additional domains of homology (DHRs) for which the function is unknown. In project #1, molecular genetic methods will be used to investigate the MAGUK DlgA, which is a component of Drosophila septate junctions and is required for maintaining septate junction structure, cell shape, polarity and proliferation control. In Project #2, biochemical methods will be used to identify proteins that interact with the MAGUKs, to map the binding sites and to investigate how binding to other proteins affects function. This project will focus on p55, which was identified from human erythrocyte membranes, and Hdlg, which was identified from lymphocytes; both proteins have been shown to bind to other proteins that link the cytoskeleton to the membrane and stabilize cell shape. Project #3 concerns the possible signalling functions of Z0-1 and Z0-2, MAGUKs localized in mammalian tight junctions required for maintaining tissue structure, transepithelial permeability barriers, and cell polarity. Project #4 will be a molecular genetic analysis of the MAGUK LIN-2 of Caenorhabditis, which contains an additional N-terminal domain homologous to calcium/calmodulin-dependent protein kinases; Project #1 also includes a genetic analysis of the corresponding Drosophila gene. Using a combination of molecular, genetic and cell biological approaches, we will determine which domains of the MAGUKs are responsible for controlling their subcellular localization, what proteins associate with them, and how they interact with known signal transduction pathways. Biochemical assays will be used to determine the catalytic and/or regulatory role of the GUK domains, and to test whether these proteins act as substrates for tyrosine kinases. The participating laboratories will bring together experimental systems with unique advantages, and they will contribute expertise in biochemistry, genetics and cell biology, to define the functions of a remarkable new family of proteins that have important roles in the control of cell structure, differentiation and proliferation.