CELL SIGNALING IN C ELEGANS

线虫中的细胞信号传导

• 批准号: 5209395
• 负责人: STEWART KIM
• 金额: --
• 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/5209395
• 关键词: Caenorhabditis elegans; biological signal transduction; cell cell interaction; confocal scanning microscopy; cytology; developmental genetics; enzyme activity; epitope mapping; female reproductive system; gene expression; gene interaction; gene mutation; genetic regulation; guanosine monophosphate; immunoprecipitation; protein structure function; protein tyrosine kinase; receptor expression; sex differentiation; site directed mutagenesis; stainings; western blottings

Cell signaling plays a fundamental role in controlling cell growth and differentiation during development. In C. elegans, one of the best understood examples of cell signaling occurs during the induction of the vulva in the hermaphrodite. Vulval development provides an opportunity to study cell signaling in vivo at single cell resolution, since induction is the result of communication between a single regulatory cell (the anchor cell) and a set of six responding cells (the vulval precursor cells). Many genes that function in the vulval cell signaling pathway have already been identified, and most are similar to genes involved in receptor tyrosine kinase pathways in mammals and Drosophila; including let-23 (a receptor tyrosine kinase gene), let-60 (a ras homolog) and mpk-1 (a MAP kinase homolog). This project began when the exciting observation was made that lin-2, a gene required for vulval induction in C. elegans, is similar to membrane- associated guanylate kinase genes (referred to as MAGUK genes) that have previously been identified in Drosophila and mammals. Studies with the C. elegans lin-2 gene provide the first direct evidence that a MAGUK gene interacts with a receptor tyrosine kinase pathway. Other MAGUK proteins may likewise interact with receptor tyrosine kinase pathways in other organisms, and elucidating the role of MAGUK proteins in signal transduction will uncover new steps in this important cell signaling pathway. One of the broad goals of this proposal is to determine how lin-2 functions during vulval cell signaling in C. elegans. Vulval development provides an ideal system for investigating the link between MAGUK proteins and signal transduction, since lin-2 function can be analyzed in the context of a well-characterized tyrosine kinase signaling pathway in which many of the genes have already been identified. By analyzing how lin-2 interacts with these other vulval signaling genes, the step in the signaling cascade that requires lin-2 function will be determined. Furthermore, a combined molecular, genetic and biochemical approach will be used to determine which of the LIN-2 protein domains and predicted enzymatic activities are required for proper cell signaling in vivo. Finally, the interactions between LIN-2 and other proteins involved in the same cellular process as LIN-2 (LIN-7 and LIN-10) will be studied. The proposed investigation of the role of lin-2 and interacting genes during vulval induction is directly relevant to abnormal signaling processes leading to tumor formation. lin-2 is similar to the Drosophila discs-large gene, which functions as a tumor suppressor gene in imaginal disc cells. Our work shows that lin-2 interacts with a highly conserved receptor tyrosine kinase signaling pathway, and constitutive activation of similar pathways in mammalian cells is oncogenic. For example, let-23, sem-5, let-60, lin-45 and lin-31 are "proto-oncogenes" since they are similar to mammalian receptor tyrosine kinase oncogenes, the crk oncogene, ras, raf and the Qin oncogene, respectively.

细胞信号在控制细胞生长和 发育过程中的分化。在线虫中，最好的之一 已理解的细胞信号转导的例子发生在 阴户在阴部的阴户。外阴发育提供了一个机会 在单细胞分辨率下研究体内细胞信号，因为诱导是 单个调节细胞(锚)之间通信的结果 细胞)和一组六个反应细胞(外阴前体细胞)。 许多在外阴细胞信号通路中起作用的基因已经 已被鉴定，并且大多数与涉及受体的基因相似 哺乳动物和果蝇中的酪氨酸激酶通路；包括let-23(a 受体酪氨酸激酶基因)、let-60(ras同源基因)和MPK-1(映射) 激酶同源物)。 这个项目是在令人兴奋的观察到LIN-2，一个 线虫外阴诱导所需的基因，类似于膜- 相关的鸟苷酸激酶基因(称为Maguk基因)具有 此前已在果蝇和哺乳动物中发现。与C. 线虫LIN-2基因首次提供了Maguk基因的直接证据 与受体酪氨酸激酶途径相互作用。其他Maguk蛋白 可能同样与其他细胞的受体酪氨酸激酶途径相互作用 生物体，并阐明Maguk蛋白在信号中的作用 转导将发现这一重要细胞信号的新步骤 路径。 这项提案的主要目标之一是确定LIN-2号如何 在线虫外阴细胞信号传递过程中的功能。外阴发育 为研究Maguk蛋白之间的联系提供了一个理想的系统 和信号转导，因为LIN-2的功能可以在 一个特征明确的酪氨酸激酶信号通路的背景 许多基因已经被识别出来。通过分析LIN-2如何 与这些其他外阴信号基因相互作用， 将确定需要LIN-2功能的信令级联。 此外，分子、遗传和生物化学相结合的方法将 用来确定哪一个LIN-2蛋白结构域并预测 体内适当的细胞信号传递需要酶的活性。 最后，LIN-2与其他蛋白之间的相互作用 将研究与LIN-2(LIN-7和LIN-10)相同的细胞过程。 LIN-2及其相互作用基因的作用研究进展 在外阴诱导过程中与异常信号直接相关 导致肿瘤形成的过程。LIN-2与果蝇相似 Diss-大基因，在想象中作为肿瘤抑制基因发挥作用 圆盘细胞。我们的工作表明，LIN-2与高度保守的 受体酪氨酸激酶信号转导通路及其组成性激活 哺乳动物细胞中类似的途径也是致癌的。例如，let-23， SEM-5、LET-60、LIN-45和LIN-31是原癌基因，因为它们是 与哺乳动物受体酪氨酸激酶癌基因类似，Crk癌基因 RAS、RAF和秦癌基因。