Structural basis of abscisic acid signalling
Structural basis of abscisic acid signalling
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DOI：
10.1038/nature08583
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发表时间：
2009-12-03
期刊：
影响因子：
64.8
通讯作者：
Tanokura, Masaru
中科院分区：
文献类型：
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作者：
Miyazono, Ken-ichi;Miyakawa, Takuya;Tanokura, Masaru
植物激素脱落酸（阿坝）介导植物对干旱等环境胁迫的适应，并调节种子成熟等发育信号。在植物中，START蛋白的PYR/PYL/RCAR家族接受阿坝以抑制A组蛋白磷酸酶2C（PP 2Cs）的磷酸酶活性，PP 2Cs是阿坝信号传导中的主要负调节剂。在这里，我们提出的晶体结构的阿坝受体PYL 1结合（+）-阿坝，并通过进一步结合（+）-ABA结合PYL 1与PP 2C蛋白ABI 1形成的复合物。PYL 1使用START蛋白特异性配体结合位点结合（+）-阿坝，从而在闭合的盖的表面上形成疏水口袋。（+）-ABA结合的PYL 1与ABI 1的PP 2C结构域紧密相互作用，通过使用疏水口袋像塞子一样覆盖ABI 1的活性位点。我们的研究结果揭示了阿坝信号中PYL 1对ABI 1的（+）-ABA依赖性抑制机制的结构基础。
The phytohormone abscisic acid (ABA) mediates the adaptation of plants to environmental stresses such as drought and regulates developmental signals such as seed maturation. Within plants, the PYR/PYL/RCAR family of START proteins receives ABA to inhibit the phosphatase activity of the group-A protein phosphatases 2C (PP2Cs), which are major negative regulators in ABA signalling. Here we present the crystal structures of the ABA receptor PYL1 bound with (+)-ABA, and the complex formed by the further binding of (+)-ABA-bound PYL1 with the PP2C protein ABI1. PYL1 binds (+)-ABA using the START-protein-specific ligand-binding site, thereby forming a hydrophobic pocket on the surface of the closed lid. (+)-ABA-bound PYL1 tightly interacts with a PP2C domain of ABI1 by using the hydrophobic pocket to cover the active site of ABI1 like a plug. Our results reveal the structural basis of the mechanism of (+)-ABA-dependent inhibition of ABI1 by PYL1 in ABA signalling.