PPKs mediate direct signal transfer from phytochrome photoreceptors to transcription factor PIF3.
PPKs mediate direct signal transfer from phytochrome photoreceptors to transcription factor PIF3.
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DOI：
10.1038/ncomms15236
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发表时间：
2017-05-11
影响因子：
16.6
通讯作者：
Quail PH
中科院分区：
文献类型：
--
作者：
Ni W;Xu SL;González-Grandío E;Chalkley RJ;Huhmer AFR;Burlingame AL;Wang ZY;Quail PH
光敏色素（phytochrome，phy）感觉光感受器在光诱导的核转位后与转录因子（称为PIFs）相互作用，并诱导其快速磷酸化和随后的泛素介导的降解，从而调节靶基因表达和植物发育。然而，phy诱导的PIF磷酸化的生化机制仍然不明确。在这里，我们确定了一个家庭的核蛋白激酶，指定光调节蛋白激酶（PPK 1 -4;以前称为MUT 9样激酶（MLKs）），与PIF 3和phyB在体内光诱导的方式相互作用。遗传分析表明，PPKs是PIF 3正常光诱导磷酸化和降解所必需的。PPK 1在体外直接磷酸化PIF 3，其磷酸化模式强烈模仿体内光诱导的模式。这些数据表明，PPK直接参与催化体内PIF 3的光活化-phy-诱导的磷酸化，因此是以转录为中心的信号中枢的关键组分，该信号中枢响应于多种信号通路而多效性地调节植物生长和发育。光敏色素光感受器介导细胞核中PIF转录因子响应于光的降解。在此，Ni等人鉴定了一个核蛋白激酶家族，其与光活化光敏色素B相互作用并促进光敏色素诱导的PIF 3磷酸化和降解。
Upon light-induced nuclear translocation, phytochrome (phy) sensory photoreceptors interact with, and induce rapid phosphorylation and consequent ubiquitin-mediated degradation of, transcription factors, called PIFs, thereby regulating target gene expression and plant development. Nevertheless, the biochemical mechanism of phy-induced PIF phosphorylation has remained ill-defined. Here we identify a family of nuclear protein kinases, designated Photoregulatory Protein Kinases (PPK1–4; formerly called MUT9-Like Kinases (MLKs)), that interact with PIF3 and phyB in a light-induced manner in vivo. Genetic analyses demonstrate that the PPKs are collectively necessary for the normal light-induced phosphorylation and degradation of PIF3. PPK1 directly phosphorylates PIF3 in vitro, with a phosphosite pattern that strongly mimics the light-induced pattern in vivo. These data establish that the PPKs are directly involved in catalysing the photoactivated-phy-induced phosphorylation of PIF3 in vivo, and thereby are critical components of a transcriptionally centred signalling hub that pleiotropically regulates plant growth and development in response to multiple signalling pathways. Phytochrome photoreceptors mediate degradation of PIF transcription factors in the nucleus in response to light. Here Ni et al. identify a family of nuclear protein kinases that interact with photoactivated phytochrome B and facilitate phytochrome-induced phosphorylation and degradation of PIF3.