2007年3月8日,，北京生命科學(xué)研究所馬力耕博士實(shí)驗(yàn)室在科學(xué)(SCIENCE)雜志在線(online)發(fā)表題為 “A G protein-coupled receptor is a plasma membrane receptor for plant hormone abscisic acid” 的論文,，該論文報(bào)道一種G蛋白偶聯(lián)受體是植物激素脫落酸（Abscisic acid，ABA）的受體,，該受體通過與異三聚體G蛋白α亞基直接相互作用傳遞脫落酸信號(hào)并調(diào)控脫落酸眾多反應(yīng),。
脫落酸是一種重要的植物激素，它參與調(diào)控眾多植物生長(zhǎng)和發(fā)育過程，特別是在植物對(duì)逆境,，如干旱,、鹽堿、低溫等的反應(yīng)中發(fā)揮重要作用,。ABA受體的研究對(duì)了解ABA的作用及其機(jī)制有非常重要的意義,。以前的眾多研究結(jié)果表明ABA的作用位點(diǎn)在質(zhì)膜上，而且這種推測(cè)的質(zhì)膜上的ABA受體可能是ABA參與逆境反應(yīng)的主要參與者,。
由G蛋白偶聯(lián)受體（GPCR）介導(dǎo)的細(xì)胞信號(hào)轉(zhuǎn)導(dǎo)途徑是在真核生物中比較保守的信號(hào)轉(zhuǎn)導(dǎo)機(jī)制,。在動(dòng)物細(xì)胞中GPCR介導(dǎo)的信號(hào)途徑是重要的信號(hào)轉(zhuǎn)導(dǎo)途徑，比如動(dòng)物對(duì)視覺,、味覺,、嗅覺的感知就是通過GPCR介導(dǎo)的信號(hào)途徑實(shí)現(xiàn)的，動(dòng)物中GPCR和G蛋白的種類也很多,，它們參與的信號(hào)轉(zhuǎn)導(dǎo)途徑和生物學(xué)功能也很多,。與此相反，高等植物中的GPCR和G蛋白的種類則非常有限,，如模式生物擬南芥基因組中只有一種Gα,，一種Gβ，2種Gγ和大約20-30種GPCR,，而且到目前為止只有一種GPCR被比較詳細(xì)地研究過,，目前植物中還沒有找到任何一種GPCR的配基。
該項(xiàng)工作鑒定了一種擬南芥中新的GPCR（GCR2）,，證實(shí)GCR2和Gα共同作用調(diào)控已知的ABA的眾多反應(yīng),。ABA可以與GCR2蛋白特異性的結(jié)合，而且這種結(jié)合符合配基-受體結(jié)合特性,。研究人員進(jìn)一步發(fā)現(xiàn)ABA與GCR2結(jié)合會(huì)導(dǎo)致GCR2-Gα蛋白復(fù)合體解離,，從而釋放出Gα使Gα進(jìn)一步激活下游的效應(yīng)器，從而證實(shí)GCR2是植物激素ABA的受體,。該項(xiàng)工作的主要貢獻(xiàn)有：1,，鑒定確認(rèn)了ABA的受體；2,，明確了ABA的信號(hào)轉(zhuǎn)導(dǎo)途徑,；3，發(fā)現(xiàn)了植物體系中的第一對(duì)配基-受體對(duì),。
該論文的第一作者是劉西崗博士,，論文的其他作者還有岳艷玲,、聶艷麗,、李薇和中國(guó)農(nóng)業(yè)大學(xué)的李斌和武維華博士。論文的通訊作者是馬力耕博士。
該項(xiàng)研究為科技部863和北京市政府資助課題,。
部分英文原文：
Submitted on October 3, 2006
Accepted on January 24, 2007
A G Protein-Coupled Receptor Is a Plasma Membrane Receptor for the Plant Hormone Abscisic Acid
Xigang Liu 1, Yanling Yue 2, Bin Li 3, Yanli Nie 2, Wei Li 4, Wei-Hua Wu 3, Ligeng Ma 1*
1 National Institute of Biological Sciences, 7 Science Park Road, Zhongguancun Life Science Park, Beijing 102206, China; Laboratory of Molecular and Cellular Biology, Hebei Normal University, Shijiazhuang, Hebei 050016, China.
2 National Institute of Biological Sciences, 7 Science Park Road, Zhongguancun Life Science Park, Beijing 102206, China.
3 State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100094, China.
4 Laboratory of Molecular and Cellular Biology, Hebei Normal University, Shijiazhuang, Hebei 050016, China.
* To whom correspondence should be addressed.
Ligeng Ma , E-mail: [email protected]
The plant hormone abscisic acid (ABA) regulates many physiological and developmental processes in plants. The mechanism of ABA perception at cell surface is not understood. Here we show that a G protein-coupled receptor genetically and physically interacts with the GPA1 to mediate all known ABA responses in Arabidopsis. Overexpressing this receptor results in an ABA-hypersensitive phenotype. This receptor binds ABA with high affinity at physiological concentration with expected kinetics and stereospecificity. The binding of ABA to the receptor leads to the dissociation of the receptor-GPA1 complex in yeast. Our results demonstrate that this G protein-coupled receptor is a plasma membrane ABA receptor.
