Phytochrome induces rapid PIF5 phosphorylation and degradation in response to red-light activation
Phytochrome induces rapid PIF5 phosphorylation and degradation in response to red-light activation
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DOI：
10.1104/pp.107.105601
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发表时间：
2007-11-01
期刊：
影响因子：
7.4
通讯作者：
Quail, Peter H.
中科院分区：
文献类型：
--
作者：
Shen, Yu;Khanna, Rajnish;Quail, Peter H.
感觉光感受器的光敏色素 (phy) 家族（拟南芥中的 phyA-phyE）在光诱导易位至细胞核后诱导靶基因表达发生变化，其中某些成员与组成型核碱性螺旋-环-螺旋转录因子家族的选定成员（例如光敏色素相互作用因子 3 (PIF3)）相互作用。先前的证据表明，光激活的光感受器分子与 PIF3 的结合会诱导细胞中转录因子的快速磷酸化，然后再通过泛素-蛋白酶体系统降解。为了研究这种明显的主要信号传导机制是否可以推广到其他 phy 相互作用伙伴，我们检查了基本螺旋-环-螺旋家族的第二个相关 phy 相互作用成员 PIF5 在早期脱黄化过程中的分子行为，即在黑暗生长的幼苗初次暴露于光后立即发生。数据显示，红光在照射后通过蛋白酶体系统诱导 PIF5 非常快速的磷酸化和随后的降解（t(1/2) < 5 分钟）。光生物学和遗传学证据表明，光激活的 phy 分子在 60 秒内起作用，诱导 PIF5 磷酸化，并且 phyA 和 phyB 冗余地主导该过程，而 phyD 发挥明显的次要作用。总的来说，这些数据支持以下观点：phy 诱导的 PIF3 和 PIF5 的快速磷酸化可能代表了从光活化光感受器到结合伴侣的主要信号转移的生化机制，并且 phyA 和 phyB（可能还有 phyD）可能利用这种共同机制向多个共享伴侣发出信号。
The phytochrome (phy) family of sensory photoreceptors (phyA-phyE in Arabidopsis thaliana) induces changes in target-gene expression upon light-induced translocation to the nucleus, where certain members interact with selected members of the constitutively nuclear basic helix-loop-helix transcription factor family, such as PHYTOCHROME-INTERACTING FACTOR3 (PIF3). Previous evidence indicates that the binding of the photoactivated photoreceptor molecule to PIF3 induces rapid phosphorylation of the transcription factor in the cell prior to its degradation via the ubiqitin-proteosome system. To investigate whether this apparent primary signaling mechanism can be generalized to other phy-interacting partners, we have examined the molecular behavior of a second related phy-interacting member of the basic helix-loop-helix family, PIF5, during early deetiolation, immediately following initial exposure of dark-grown seedlings to light. The data show that red light induces very rapid phosphorylation and subsequent degradation (t(1/2) < 5 min) of PIF5 via the proteosome system upon irradiation. Photobiological and genetic evidence indicates that the photoactivated phy molecule acts within 60 s to induce this phosphorylation of PIF5, and that phyA and phyB redundantly dominate this process, with phyD playing an apparently minor role. Collectively, the data support the proposal that the rapid phy-induced phosphorylation of PIF3 and PIF5 may represent the biochemical mechanism of primary signal transfer from photoactivated photoreceptor to binding partner, and that phyA and phyB (and possibly phyD) may signal to multiple, shared partners utilizing this common mechanism.