脫落酸（ABA）是一種主要植物激素,，其作用是保護(hù)植物不受干旱和低溫等壓力影響,，并且在氣孔打開和種子休眠等日常響應(yīng)中發(fā)揮作用,。在ABA通道中作為受體而引人注目的是PYR/PYL/RCAR家族的蛋白以及2-型磷酸酶ABI1,、ABI2 和PP2C,，它們抑制ABA信號作用。
現(xiàn)在,，三個小組報告了ABA在非結(jié)合狀態(tài)及在包括PYL2-ABA-PP2C和PYL1-ABA-ABI1在內(nèi)的不同復(fù)合物中的晶體結(jié)構(gòu),。這些結(jié)構(gòu)表明，PYL/ABA生成一個與PP2C 和ABI1相結(jié)合的疏水穴,，同時結(jié)合生化研究,，這些結(jié)構(gòu)還為ABA信號作用指出了一個機(jī)制（Articles pp. 602, 609; Letter p. 665）。Jian-Kang Zhu及其同事在試管中重構(gòu)了ABA信號通道（這對植物激素來說是第一次）,，并在活體中對關(guān)鍵觀測結(jié)果進(jìn)行了驗證,。（生物谷Bioon.com）
更多脫落酸研究：
NSMB：脫落酸受體介導(dǎo)脫落酸信號傳導(dǎo)的分子機(jī)制
Cell：發(fā)現(xiàn)兩種新型脫落酸受體
Nature：蛋白質(zhì)PYR1調(diào)節(jié)植物抗旱機(jī)制
Science：確認(rèn)新的ABA受體
《自然》準(zhǔn)備撤銷高被引植物學(xué)論文
生物谷推薦原始出處：
Nature 462, 602-608 (3 December 2009) | doi:10.1038/nature08613
A gate–latch–lock mechanism for hormone signalling by abscisic acid receptors near-final version
Karsten Melcher1,7, Ley-Moy Ng1,2,7, X. Edward Zhou1,7, Fen-Fen Soon1,2,7, Yong Xu1, Kelly M. Suino-Powell1, Sang-Youl Park3, Joshua J. Weiner4, Hiroaki Fujii3,5, Viswanathan Chinnusamy3,5, Amanda Kovach1, Jun Li1,2, Yonghong Wang6, Jiayang Li6, Francis C. Peterson4, Davin R. Jensen4, Eu-Leong Yong2, Brian F. Volkman4, Sean R. Cutler3, Jian-Kang Zhu3,5 & H. Eric Xu1
1 Laboratory of Structural Sciences, Van Andel Research Institute, 333 Bostwick Avenue, N.E., Grand Rapids, Michigan 49503, USA
2 Department of Obstetrics & Gynecology, National University Hospital, Yong Loo Lin School of Medicine, Graduate School for Integrative Sciences & Engineering, National University of Singapore, Singapore 119074, Republic of Singapore
3 Department of Botany and Plant Sciences, University of California at Riverside, Riverside, California 92521, USA
4 Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA
5 Center for Plant Stress Genomics and Technology, King Abdullah University of Science and Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia
6 State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, National Center for Plant Gene Research, Beijing 100101, China
7 These authors contributed equally to this work.
Correspondence to: H. Eric Xu1 Correspondence and requests for materials should be addressed to H.E.X.
Abscisic acid (ABA) is a ubiquitous hormone that regulates plant growth, development and responses to environmental stresses. Its action is mediated by the PYR/PYL/RCAR family of START proteins, but it remains unclear how these receptors bind ABA and, in turn, how hormone binding leads to inhibition of the downstream type 2C protein phosphatase (PP2C) effectors. Here we report crystal structures of apo and ABA-bound receptors as well as a ternary PYL2–ABA–PP2C complex. The apo receptors contain an open ligand-binding pocket flanked by a gate that closes in response to ABA by way of conformational changes in two highly conserved -loops that serve as a gate and latch. Moreover, ABA-induced closure of the gate creates a surface that enables the receptor to dock into and competitively inhibit the PP2C active site. A conserved tryptophan in the PP2C inserts directly between the gate and latch, which functions to further lock the receptor in a closed conformation. Together, our results identify a conserved gate–latch–lock mechanism underlying ABA signalling.
