Characterization of a novel mammalian RGS protein that binds to G alpha proteins and inhibits pheromone signaling in yeast
Characterization of a novel mammalian RGS protein that binds to G alpha proteins and inhibits pheromone signaling in yeast
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DOI：
10.1074/jbc.272.13.8679
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发表时间：
1997-03-28
影响因子：
4.8
通讯作者：
Lin, SC
中科院分区：
文献类型：
--
作者：
Chen, CH;Zheng, B;Lin, SC
对负调节G偶联受体功能的分子的遗传学研究导致了一个具有进化保守结构域的大基因家族的鉴定，称为RGS结构域。现已认识到，RGS蛋白是异源三聚体G蛋白亚家族的GTP酶激活蛋白。我们从小鼠脑垂体中分离到一个编码RGS蛋白家族新成员的全长cDNA克隆，命名为RGS16，以及mRGS5和mRGS2的全长cDNA。组织分布分析表明，新的RGS16主要在肝脏和脑垂体中表达，RGS5在心肌和骨骼肌中优先表达。相反，RGS2被广泛表达。利用信息素反应晕环和FUS1基因诱导的遗传分析表明，RGS16基因的过表达显著抑制酵母对Cy因子的反应，而RGS2和RGS5对信息素敏感性没有明显影响，这表明RGS蛋白之间可能存在功能差异。体外结合分析表明，RGS5和RGS16与异源三聚体G蛋白的Gα(I)和Gα(O)亚基结合，但不与Gα结合(S)。基于对RGS结构域保守残基的突变分析，我们认为G蛋白结合和GTP酶激活蛋白的活性可能与RGS蛋白不同的功能结构有关，表明RGS蛋白可能通过G偶联受体在信号减弱中发挥双重功能。
Genetic studies of molecules that negatively regulate G-coupled receptor functions have led to the identification of a large gene family with an evolutionarily conserved domain, termed the RGS domain. It is now understood that RGS proteins serve as GTPase-activating proteins for subfamilies of the heterotrimeric G-proteins. We have isolated from mouse pituitary a full-length cDNA clone encoding a novel member of the RGS protein family, termed RGS16, as well as the full-length cDNA of mRGS5 and mRGS2. Tissue distribution analysis shows that the novel RGS16 is predominantly expressed in liver and pituitary, and that RGS5 is preferentially expressed in heart and skeletal muscle. In contrast, RGS2 is widely expressed. Genetic analysis using the pheromone response halo assay and FUS1 gene induction assay show that overexpression of the RGS16 gene dramatically inhibits yeast response to cy-factor, whereas neither RGS2 nor RGS5 has any discernible effect on pheromone sensitivity, pointing to a possible functional diversity among RGS proteins. In vitro binding assays reveal that RGS5 and RGS16 bind to G alpha(i) and G alpha(o) subunits of heterotrimeric G-proteins, but not to G alpha(s). Based on mutational analysis of the conserved residues in the RGS domain, we suggest that the G-protein binding and GTPase-activating protein activity may involve distinct functional structures of the RGS proteins, indicating that RGS proteins may exert a dual function in the attenuation of signaling via G-coupled receptors.