PHEROMONE RESPONSE AND G PROTEINS IN YEAST

酵母中的信息素反应和 G 蛋白

• 批准号: 3298293
• 负责人: JANET A. KURJAN
• 金额: $ 27.55万
• 依托单位: COLUMBIA UNIV NEW YORK MORNINGSIDE
• 依托单位国家: 美国
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-04-01 至 1993-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3298293
• 关键词: G protein; binding proteins; enzyme mechanism; fungal genetics; gene complementation; gene expression; genetic manipulation; genetic transduction; guanine nucleotides; guanosinetriphosphatases; hormone receptor; laboratory rabbit; molecular cloning; molecular genetics; nucleic acid hybridization; pheromone; point mutation; temperature sensitive mutant

The a and alpha mating types in yeast secrete and respond to the peptide pheromones, a-factor and alpha-factor. The response is initiated by binding of pheromone to a specific receptor present on cells of the opposite mating type. The structures of the a- and alpha-factor receptors are very similar to the structures of receptors in vertebrate signal transduction pathways mediated by G (guanine nucleotide-binding) proteins, including the phototransduction and the beta-adrenergic response pathways. The yeast SST2 and SCG1 genes were isolated by complementation of a pheromone response mutation (sst2). These genes encode proteins that are likely to play important roles in the pheromone response pathway common to both mating types. SST2 is proposed to play a role in desensitization to pheromone similar to the role of arrestin in desensitization of the phototransduction pathway. SCG1 shows a high degree of homology to the G proteins involved in other signal transduction systems. The purpose of the proposed research is to further characterize the roles of the SST2 and SCG1 products in the pheromone response pathway, to test specific models for SST2 and SCG1 function, to identify additional components of this pathway, and to further investigate similarities to vertebrate signal transduction systems. Further analysis of SST2 and SCG1 function will involve examination of the effect of overproduction on pheromone response and mating, screens for change-of- function mutations, and localization of the protein products both in the absence and presence of pheromone. SCG1 function will also be analyzed by assays for guanine nucleotide-binding and GTPase activities associated with G proteins and by construction of site-directed mutations to examine the effects of amino acid substitutions that have been shown to effect the function of other guanine nucleotide-binding proteins. Additional clones that complement sst2 may encode other components of the pheromone response pathway and therefore will be analyzed. Suppressors of sst2 or scg1 loss-of-function and change-of-function mutations will be isolated; mutations in components of the response pathway should be identified among the suppressors. Finally, hybridization analysis has indicated that there are additional yeast sequences homologous to SCG1; these sequences will be analyzed to identify additional G proteins involved in pheromone response and other interesting processes.

酵母中的α和α交配类型分泌并响应 肽信息素、α因子和α因子。 响应是 由信息素与存在的特定受体结合引发 在相反交配类型的细胞上。 a-和的结构 α因子受体的结构与 脊椎动物信号转导途径中的受体 G（鸟嘌呤核苷酸结合）蛋白，包括 光转导和β-肾上腺素能反应途径。 酵母 SST2 和 SCG1 基因通过以下方法分离： 信息素反应突变（sst2）的互补。 这些 基因编码的蛋白质可能在以下方面发挥重要作用： 两种交配类型共有的信息素反应途径。 SST2被认为在信息素脱敏中发挥作用 类似于视紫红质抑制蛋白的脱敏作用 光转导途径。 SCG1显示出高度 与参与其他信号转导的 G 蛋白同源 系统。 拟议研究的目的是进一步表征 SST2和SCG1产物在信息素中的作用 响应途径，测试 SST2 和 SCG1 的特定模型 功能，以确定该途径的其他成分，以及 进一步研究与脊椎动物信号的相似性 转导系统。 SST2和SCG1的进一步分析 职能将涉及检查生产过剩的影响 关于信息素反应和交配，筛选变化- 功能突变和蛋白质产物的定位 在信息素不存在和存在的情况下。 SCG1 功能将 还可以通过鸟嘌呤核苷酸结合分析进行分析 与 G 蛋白相关的 GTP 酶活性及其构建 定点突变以检查氨基酸的影响 已被证明会影响其他功能的替代 鸟嘌呤核苷酸结合蛋白。 额外的克隆 补体 sst2 可能编码信息素的其他成分 反应途径，因此将被分析。 抑制剂 sst2 或 scg1 功能丧失和功能改变突变 会被孤立；反应途径成分的突变 应在抑制器中进行识别。 最后，杂交 分析表明还有额外的酵母序列 与SCG1同源；这些序列将被分析以确定 参与信息素反应的其他 G 蛋白和其他 有趣的过程。