GTPase acceleration as the rate-limiting step in Arabidopsis G protein-coupled sugar signaling
GTPase acceleration as the rate-limiting step in Arabidopsis G protein-coupled sugar signaling
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DOI：
10.1073/pnas.0704751104
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发表时间：
2007-10-30
影响因子：
11.1
通讯作者：
Willard, Francis S.
中科院分区：
文献类型：
--
作者：
Johnston, Christopher A.;Taylor, J. Philip;Willard, Francis S.
异源三聚体G蛋白信号在模式植物拟南芥的细胞增殖和葡萄糖传感信号转导途径中是重要的。AtRGS1是一种含RGS结构域的七跨膜蛋白，被认为是d -葡萄糖的膜受体。在这里，我们通过FRET显示，d -葡萄糖在体内改变AtGPA1和AtRGS1之间的相互作用。AtGPA1是一种独特的异三聚体G蛋白，由于其高自发核苷酸交换和缓慢的GTP水解，它是GTP结合的亚基。对AtRGS1点突变的分析表明，在拟南芥发育过程中，AtGPA1 GTP水解的调节介导了糖信号转导，而在动物中，核苷酸交换是异源三聚体G蛋白核苷酸循环的限制步骤。
Heterotrimeric G protein signaling is important for cell-proliferative and glucose-sensing signal transduction pathways in the model plant, organism Arabidopsis thaliana. AtRGS1 is a seven-transmembrane, RGS domain-containing protein that is a putative membrane receptor for D-glucose. Here we show, by using FRET, that D-glucose alters the interaction between the AtGPA1 and AtRGS1 in vivo. AtGPA1 is a unique heterotrimeric G protein a subunit that is constitutively GTP-bound given its high spontaneous nucleotide exchange coupled with slow GTP hydrolysis. Analysis of a point mutation in AtRGS1 that abrogates GTPase-accelerating activity demonstrates that the regulation of AtGPA1 GTP hydrolysis mediates sugar signal transduction during Arabidopsis development, in contrast to animals where nucleotide exchange is the limiting step in the heterotrimeric G protein nucleotide cycle.