GENETIC FINE-STRUCTURAL ANALYSIS OF THE SACCHAROMYCES-CEREVISIAE ALPHA-PHEROMONE RECEPTOR
GENETIC FINE-STRUCTURAL ANALYSIS OF THE SACCHAROMYCES-CEREVISIAE ALPHA-PHEROMONE RECEPTOR
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DOI：
10.1091/mbc.2.6.439
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发表时间：
1991-06-01
期刊：
影响因子：
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通讯作者：
JENNESS, DD
中科院分区：
文献类型：
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作者：
KONOPKA, JB;JENNESS, DD
STE2 基因编码的α-信息素受体包含七个潜在的跨膜结构域。人们认为其转导信息素信号的能力需要 G 蛋白的作用。作为定义其活性所需受体结构特征的第一步，我们检查了 STE2 基因 10 个不同位点的接头插入突变 (12 bp) 的表型后果。观察到三个突变类别，对应于受体蛋白的三个不同区域。 1）影响C端区域的两个突变体（C端突变体）在交配效率、信息素结合和信息素敏感性方面本质上是野生型。 2）N端的三个突变体交配效率降低，表现出信息素结合能力降低，并且在信息素诱导凝集素产生和细胞分裂停滞方面部分缺陷。这些 N 末端等位基因的基因剂量增加抑制了它们的突变表型，而阻止对信息素适应的 sst2-1 突变并没有导致抑制。因此，N端突变体显然受到受体产生的限制，但不受适应功能SST2的限制。3）包含七个跨膜片段的中心区域的五个突变体（中心突变体）完全没有交配缺陷，并且对信息素没有反应，但可以通过它们结合信息素的能力来区分。跨膜结构域 2 和 4 中或附近的插入阻断了信息素结合，而跨膜结构域 1、5 和 6 中的插入保留了部分信息素结合活性，即使它们未能转导信号。增加基因剂量不会抑制中心突变体，并且一种突变体（ste2-I101）被 sst2-1 部分抑制。此外，中央核心突变体也彼此不同，因为五个突变体中的三个能够部分补充ste2-3的温度敏感性。
The alpha-pheromone receptor encoded by the STE2 gene contains seven potential transmembrane domains. Its ability to transduce the pheromone signal is thought to require the action of a G protein. As an initial step toward defining the structural features of the receptor required for its activity, we examined the phenotypic consequences of linker insertion mutations (12 bp) at 10 different sites in the STE2 gene. Three mutant classes, which correspond to three different regions of the receptor protein, were observed. 1) The two mutants affecting the C-terminal region (C-terminal mutants) were essentially wild type for mating efficiency, pheromone binding, and pheromone sensitivity. 2) The three mutants in the N-terminus mated with reduced efficiency, showed reduced pheromone binding capacity, and were partially defective in pheromone induction of agglutinin production and cell division arrest. Increased gene dosage of these N-terminal alleles suppressed their mutant phenotypes, whereas the sst2-1 mutation, which blocks adaptation to pheromone, did not result in suppression. Thus, the N-terminal mutants were apparently limited by receptor production, but not by the adaptation function SST2.3) The five mutants in the central region containing the seven transmembrane segments (central mutants) were completely defective for mating and did not respond to pheromone, but could be distinguished by their ability to bind pheromone. Inserts in or near transmembrane domains 2 and 4 blocked pheromone binding, whereas inserts into transmembrane domains 1, 5, and 6 retained partial pheromone binding activity even though they failed to transduce a signal. The central mutants were not suppressed by increased gene dosage, and one mutant (ste2-I101) was partially suppressed by sst2-1. Furthermore, the central core mutants were also distinguished from one another in that three of the five mutants were able to partially complement the temperature sensitivity of ste2-3.