Allosteric deactivation of PIFs and EIN3 by microproteins in light control of plant development
Allosteric deactivation of PIFs and EIN3 by microproteins in light control of plant development
复制标题
微生物蛋白对 PIF 和 EIN3 的变构失活在光控制植物发育中的作用
DOI：
10.1073/pnas.2002313117
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发表时间：
2020-08-04
影响因子：
11.1
通讯作者：
Zhong，Shangwei
中科院分区：
文献类型：
--
作者：
Wu，Qingqing;Kuang，Kunyan;Zhong，Shangwei
意义植物如何响应和调整其生长以应对环境变化是生物学中一个长期存在的问题。通过对初始暗-光转换的研究，我们揭示了植物通过施加微蛋白抑制蛋白质活性来实现从干形态建成到光形态建成的快速转换。微蛋白是动物体内必需的生物活性调节因子。在植物中预测了大量的微蛋白，但很少有功能特征。我们鉴定了两种微蛋白，它们是光刺激的组织特异性的，直接干扰光信号中关键转录因子的寡聚。这种微蛋白导向的变构失活可以被用来开发在分子育种中对目标蛋白进行翻译后调节的通用工具。当掩埋的幼苗从土壤中出现在阳光下时，它们经历了戏剧性的发育转变。作为抑制光反应的中心转录因子，光敏色素相互作用因子(PIF)和乙烯不敏感3(EIN3)在黑暗中发挥作用，必须在光下迅速抑制才能启动脱黄化。微蛋白是进化上保守的小分子单域蛋白，在真核生物中充当翻译后调节因子。虽然预测植物中存在成千上万的微蛋白，但它们的目标分子、生物学作用和作用机制在很大程度上仍不清楚。在这里，我们证明了两种微蛋白，miP1a和miP1b(miP1a/b)，在从暗到光的转变中受到强烈的刺激。MiP1a/b主要在子叶和下胚轴中表达，表现出与PIF和EIN3相似的组织特异性模式。我们证明了PIFs和EIN3通过自我相互作用组装功能低聚物，而miP1a/b通过形成非功能蛋白质复合体直接与PIFs和EIN3相互作用并破坏其寡聚。结果，PIFs和EIN3的DNA结合能力和转录活性明显受到抑制。这些生化发现进一步得到了遗传证据的支持。MiP1a/b正向调控光形态发生，组成性表达miP1a/b挽救了高表达PIFs和EIN3植物顶端钩的延迟展开和子叶的发育。我们的研究表明，微蛋白对主要转录因子的寡聚化提供了一种时间和负面的控制，以实现随着环境变化而及时的发育过渡。
Significance How plants respond and adjust their growth to cope with environmental changes is a long-standing question in biology. By studying the initial dark-to-light transition, we reveal that a microprotein-imposed suppression of protein activity is adopted by plants to achieve rapid switch from skotomorphogenic to photomorphogenic programs. Microproteins are essential bioactive regulators in animals. A large number of microproteins are predicted in plants, but very few of them are functionally characterized. We identified two microproteins that are tissue-specifically stimulated by light and directly disrupt the oligomerization of key transcription factors in light signaling. This microprotein-directed allosteric deactivation can be utilized to develop versatile tools for posttranslational regulation of target proteins in molecular breeding. Buried seedlings undergo dramatic developmental transitions when they emerge from soil into sunlight. As central transcription factors suppressing light responses, PHYTOCHROME-INTERACTING FACTORs (PIFs) and ETHYLENE-INSENSITIVE 3 (EIN3) actively function in darkness and must be promptly repressed upon light to initiate deetiolation. Microproteins are evolutionarily conserved small single-domain proteins that act as posttranslational regulators in eukaryotes. Although hundreds to thousands of microproteins are predicted to exist in plants, their target molecules, biological roles, and mechanisms of action remain largely unknown. Here, we show that two microproteins, miP1a and miP1b (miP1a/b), are robustly stimulated in the dark-to-light transition. miP1a/b are primarily expressed in cotyledons and hypocotyl, exhibiting tissue-specific patterns similar to those of PIFs and EIN3. We demonstrate that PIFs and EIN3 assemble functional oligomers by self-interaction, while miP1a/b directly interact with and disrupt the oligomerization of PIFs and EIN3 by forming nonfunctional protein complexes. As a result, the DNA binding capacity and transcriptional activity of PIFs and EIN3 are predominantly suppressed. These biochemical findings are further supported by genetic evidence. miP1a/b positively regulate photomorphogenic development, and constitutively expressing miP1a/b rescues the delayed apical hook unfolding and cotyledon development of plants overexpressing PIFs and EIN3. Our study reveals that microproteins provide a temporal and negative control of the master transcription factors' oligomerization to achieve timely developmental transitions upon environmental changes.