A thermodynamic switch modulates abscisic acid receptor sensitivity
A thermodynamic switch modulates abscisic acid receptor sensitivity
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DOI：
10.1038/emboj.2011.294
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发表时间：
2011-10-19
期刊：
影响因子：
11.4
通讯作者：
Marquez, Jose Antonio
中科院分区：
文献类型：
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作者：
Dupeux, Florine;Santiago, Julia;Marquez, Jose Antonio
脱落酸(ABA)是调节植物生长发育以及对生物和非生物胁迫反应的关键激素。ABA与PYR/PYR1样(PYL)/脱落酸受体调节成分(RCAR)细胞内受体的结合促进与某些蛋白磷酸酶2C(PP2Cs)形成稳定的复合体，导致ABA信号的激活。PYR/PYL/RCAR家族在拟南芥中包含14个基因，是目前已知的最大的植物激素受体家族；然而，目前还不清楚受体之间存在什么功能差异。在这里，我们识别了两类不同的受体，二聚体和单体，它们对ABA具有不同的内在亲和力，它们的不同性质由它们的载脂蛋白形式的低聚状态决定。此外，我们在PYR1，H60中发现了一个残基，该残基在家庭成员之间是可变的，并且在决定低聚状态方面起着关键作用。在电子计算机中，对ABA激活途径的模拟表明，单体受体在与ABA和PP2Cs结合方面具有竞争优势。这项工作说明了受体寡聚如何调节激素反应，以及更广泛地说，配体依赖的信号系统的敏感性。
Abscisic acid (ABA) is a key hormone regulating plant growth, development and the response to biotic and abiotic stress. ABA binding to pyrabactin resistance (PYR)/PYR1-like (PYL)/Regulatory Component of Abscisic acid Receptor (RCAR) intracellular receptors promotes the formation of stable complexes with certain protein phosphatases type 2C (PP2Cs), leading to the activation of ABA signalling. The PYR/PYL/RCAR family contains 14 genes in Arabidopsis and is currently the largest plant hormone receptor family known; however, it is unclear what functional differentiation exists among receptors. Here, we identify two distinct classes of receptors, dimeric and monomeric, with different intrinsic affinities for ABA and whose differential properties are determined by the oligomeric state of their apo forms. Moreover, we find a residue in PYR1, H60, that is variable between family members and plays a key role in determining oligomeric state. In silico modelling of the ABA activation pathway reveals that monomeric receptors have a competitive advantage for binding to ABA and PP2Cs. This work illustrates how receptor oligomerization can modulate hormonal responses and more generally, the sensitivity of a ligand-dependent signalling system.