Analysis of the receptor binding domain of Gpa1p, the G(alpha) subunit involved in the yeast pheromone response pathway.
Analysis of the receptor binding domain of Gpa1p, the G(alpha) subunit involved in the yeast pheromone response pathway.
复制标题
分析 Gpa1p 的受体结合域，Gpa1p 是参与酵母信息素响应途径的 G(α) 亚基。
DOI：
10.1128/mcb.17.5.2897
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发表时间：
1997
影响因子：
5.3
通讯作者：
Kurjan,J
中科院分区：
文献类型：
--
作者：
Kallal,L;Kurjan,J
酿酒酵母 G 蛋白 α 亚基 Gpa1p 参与 MATa 和 MATα 细胞对信息素的反应。我们对 GPA1C 末端进行诱变以表征受体相互作用结构域并研究与 a 和 α 因子受体相互作用的特异性。讨论了基于牛转导蛋白晶体结构的 Gpa1p C 末端结构模型的结果。一些突变体表现出与影响受体相互作用的突变所预期的信息素反应和交配缺陷不同的表型，因此这些突变可能会影响 Gpa1p 功能的其他方面。大多数导致信息素反应和交配缺陷的突变在 MATa 和 MATα 细胞中具有相似的效果，表明它们影响与两种受体的相互作用。信息素受体的过度表达增加了一些测试突变体的交配，但不增加野生型菌株的交配，这与突变体 Gpa1p 受体相互作用的缺陷一致。交配缺陷突变体识别的区域与涉及受体相互作用的哺乳动物 Gα 亚基区域密切相关。脯氨酸突变和预计形成 C 末端 β 转角的甘氨酸残基突变的交配类型特异性效应最强。哺乳动物 Gα 亚基中类似的 β 转角在受体相互作用时会发生构象变化。我们提出，Gpa1p 该区域的构象在与 a 因子受体和 α 因子受体相互作用期间有所不同，并且这些交配类型特异性突变排除了与两种受体之一相互作用所需的方向。
TheSaccharomyces cerevisiaeG protein α subunit Gpa1p is involved in the response of bothMATa andMATα cells to pheromone. We mutagenized theGPA1C terminus to characterize the receptor-interacting domain and to investigate the specificity of the interactions with the a- and α-factor receptors. The results are discussed with respect to a structural model of the Gpa1p C terminus that was based on the crystal structure of bovine transducin. Some mutants showed phenotypes different than the pheromone response and mating defects expected for mutations that affect receptor interactions, and therefore the mutations may affect other aspects of Gpa1p function. Most of the mutations that resulted in pheromone response and mating defects had similar effects inMATa andMATα cells, suggesting that they affect the interactions with both receptors. Overexpression of the pheromone receptors increased the mating of some of the mutants tested but not the wild-type strain, consistent with defects in mutant Gpa1p-receptor interactions. The regions identified by the mating-defective mutants correlated well with the regions of mammalian Gαsubunits implicated in receptor interactions. The strongest mating type-specific effects were seen for mutations to proline and a mutation of a glycine residue predicted to form a C-terminal β turn. The analogous β turn in mammalian Gαsubunits undergoes a conformational change upon receptor interaction. We propose that the conformation of this region of Gpa1p differs during the interactions with the a- and α-factor receptors and that these mating type-specific mutations preclude the orientation necessary for interaction with one of the two receptors.