MEMBRANE-ASSOCIATED GUANYLATE KINASE HOMOLOGS

通过四个实验室的合作和个人努力， 建议对新成立的联合国系统的职能进行协调分析， 发现了名为MAGUKs（膜相关鸟苷酸）的蛋白质家族 激酶同源物），似乎具有重要的结构和信号传导 在无脊椎动物和脊椎动物的细胞膜上的作用。这些 蛋白质都含有与鸟苷酸激酶（GUK）同源的结构域， SH 3结构域和一个或三个另外的同源结构域（DHR）， 其功能未知。在项目#1中，分子遗传学方法 将被用于调查MAGUK DlgA，这是一个组成部分， 果蝇的分隔连接， 连接结构、细胞形状、极性和增殖控制。在 项目#2，生物化学方法将用于识别蛋白质， 与MAGUKs相互作用，绘制结合位点，并研究如何 与其他蛋白质结合会影响功能。该项目将重点关注 从人红细胞膜中鉴定的p55，和Hdlg， 这两种蛋白质都被证明是 与其他蛋白质结合，这些蛋白质将细胞骨架连接到细胞膜上， 稳定细胞形状。项目#3涉及可能的信令 Z 0 -1和Z 0 -2的功能，MAGUKs定位于哺乳动物紧密连接 维持组织结构、跨上皮渗透性 屏障和细胞极性。项目#4将是一个分子遗传学 分析小杆线虫的MAGUK LIN-2，其含有 与钙/钙调蛋白依赖性同源的额外N-末端结构域 蛋白激酶;项目#1还包括一个基因分析， 对应的果蝇基因。利用分子遗传 和细胞生物学方法，我们将确定哪些领域的 MAGUK负责控制其亚细胞定位， 与之相关的蛋白质，以及它们如何与已知的信号相互作用， 转导途径。将使用生物化学测定来确定 GUK结构域的催化和/或调节作用，并测试是否 这些蛋白质充当酪氨酸激酶的底物。与会 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， 和细胞生物学，以确定一个显着的新家庭的功能， 在控制细胞结构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.