RAS EFFECTOR COMPLEX OF S CEREVISIAE

这里提出的研究旨在加强我们的理解 导致癌症的信号通路。 癌症是 由一组称为原- 致癌基因 最常见的突变原癌基因之一是 ras癌基因。 这个项目将研究与ras基因相互作用的蛋白质 酿酒酵母的同源物。 这种酵母是 只有ras具有明确功能的生物体，cAMP 信号通路 酵母和哺乳动物ras都激活 酵母腺苷酸环化酶。 腺苷酸环化酶。酿酒酵母含有 至少两个亚基，200 kDa催化亚基和70 kDa催化亚基， 环化酶相关蛋白。 CAP是双功能的， cAMP水平的正调节剂并介导非cAMP信号 也 CAP和腺苷酸环化酶如何相互作用的细节将在 通过生化绘图研究探索。 的性质 腺苷酸环化酶在其CAP结合和无CAP的形式将是 在酶动力学实验中研究，特别注意 CAP可能对腺苷酸环化酶的激活产生的任何影响， RAS。 CAP的非cAMP功能将通过鉴定 以及克隆CAP诱导表型的抑制子。 最后， 哺乳动物cDNA文库将使用酵母遗传学筛选， 鉴定哺乳动物CAP非cAMP抑制因子的试验 功能 总之，这些研究将增强我们对RAS如何的理解。 与其唯一已知的效应子S.酿酒腺甘醯基 环化酶，然后测试在何种程度上，其中一些 相互作用在哺乳动物中是保守的。

The studies proposed here are designed to enhance our understanding of the signalling pathways that lead to cancer. Cancer is a disease caused by mutations in a group of genes known as proto- oncogenes. One of the most commonly mutated proto-oncogenes is the ras oncogene. This project will study proteins that interact with the ras gene homologs of the yeast Saccharomyces cerevisiae. This yeast is the only organism which ras has a well defined function, the cAMP signalling pathway. Yeast, and also mammalian ras both activate yeast adenylyl cyclase. Adenylyl cyclase in S. cerevisiae contains at least two subunits, a 200 kDa catalytic subunit and a 70 kDa cyclase associated protein, CAP. CAP is bifunctional, serving as a positive regulator of cAMP levels and mediating a non-cAMP signal as well. The details of how CAP and adenylyl cyclase interact will be explored through biochemical mapping studies. The properties of adenylyl cyclase in its CAP-bound and CAP-free forms will be studied in enzyme kinetic experiments, paying particular attention to any influence CAP may have on activation of adenylyl cyclase by RAS. The non-cAMP function of CAP will be studied by identifying and cloning suppressors of CAP induced phenotypes. Finally, mammalian cDNA libraries will be screened using yeast genetic assays to identify mammalian suppressors of the CAP non-cAMP function. Together these studies will enhance our understanding of how ras interacts with its only known effector, S. cerevisiae adenylyl cyclase, and then test the extent to which some of these interactions are conserved in mammals.