A gate-latch-lock mechanism for hormone signalling by abscisic acid receptors

Karsten Melcher, Ley-Moy Ng, X. Edward Zhou, Fen-Fen Soon, Yong Xu, Kelly M. Suino-Powell, Sang-Youl Park, Joshua J. Weiner, Hiroaki Fujii, Viswanathan Chinnusamy, Amanda Kovach, Jun Li, Yonghong Wang, Jiayang Li, Francis C. Peterson, Davin R. Jensen, Eu-Leong Yong, Brian F. Volkman, Sean R. Cutler, Jian-Kang ZhuH. Eric Xu

Research output: Contribution to journalArticlepeer-review

552 Scopus citations


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. © 2009 Macmillan Publishers Limited. All rights reserved.
Original languageEnglish (US)
Pages (from-to)602-608
Number of pages7
Issue number7273
StatePublished - Dec 3 2009

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KAUST Repository Item: Exported on 2020-10-01

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