Destabilization of strigolactone receptor DWARF14 by binding of ligand and E3-ligase signaling effector DWARF3
Destabilization of strigolactone receptor DWARF14 by binding of ligand and E3-ligase signaling effector DWARF3
复制标题
配体和 E3 连接酶信号效应子 DWARF3 结合导致独脚金内酯受体 DWARF14 不稳定
DOI：
10.1038/cr.2015.122
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发表时间：
2015-11-01
期刊：
影响因子：
44.1
通讯作者：
Xu, H. Eric
中科院分区：
文献类型：
--
作者：
Zhao, Li-Hua;Zhou, X. Edward;Xu, H. Eric
独脚金内酯（SL）是植物对低水平矿质营养响应的内源激素和分泌的信号分子。水稻中SL信号传导途径的关键介质包括α/β-折叠水解酶DWARF 14（D14）和泛素连接酶SCFD 3的F-盒组分DWARF 3（D3），其介导下游信号传导阻遏物的配体依赖性降解。一个令人困惑的特征是，D14不仅作为SL受体发挥作用，而且还是一种活性酶，其缓慢水解包括GR 24在内的各种天然和合成SL，防止D14与完整SL的二元复合物以及三元D14/SL/D3复合物结晶。在这里，我们克服了这些障碍，得到一个结构模型的D14结合完整的GR 24和确定的接口，需要GR 24介导的D14-D3相互作用。GR 24介导的信号传导模式，包括配体识别、D14水解和配体介导的D14-D3相互作用，在结构多样的SL中是保守的。更重要的是，D14在配体和D3结合时不稳定，从而揭示了SL识别和信号传导的不寻常机制，其中激素、受体和下游效应物在信号转导过程中系统地不稳定。
Strigolactones (SLs) are endogenous hormones and exuded signaling molecules in plant responses to low levels of mineral nutrients. Key mediators of the SL signaling pathway in rice include the alpha/beta-fold hydrolase DWARF 14 (D14) and the F-box component DWARF 3 (D3) of the ubiquitin ligase SCFD3 that mediate ligand-dependent degradation of downstream signaling repressors. One perplexing feature is that D14 not only functions as the SL receptor but is also an active enzyme that slowly hydrolyzes diverse natural and synthetic SLs including GR24, preventing the crystallization of a binary complex of D14 with an intact SL as well as the ternary D14/SL/D3 complex. Here we overcome these barriers to derive a structural model of D14 bound to intact GR24 and identify the interface that is required for GR24-mediated D14-D3 interaction. The mode of GR24-mediated signaling, including ligand recognition, hydrolysis by D14, and ligand-mediated D14-D3 interaction, is conserved in structurally diverse SLs. More importantly, D14 is destabilized upon the binding of ligands and D3, thus revealing an unusual mechanism of SL recognition and signaling, in which the hormone, the receptor, and the downstream effectors are systematically destabilized during the signal transduction process.