Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Plant Commun. 2020 Jun 2;1(5):100080. doi: 10.1016/j.xplc.2020.100080. eCollection 2020 Sep 14.
Small ubiquitin-like modifier (SUMO) post-translational modification (SUMOylation) plays essential roles in regulating various biological processes; however, its function and regulation in the plant light signaling pathway are largely unknown. SEUSS (SEU) is a transcriptional co-regulator that integrates light and temperature signaling pathways, thereby regulating plant growth and development in . Here, we show that SEU is a substrate of SUMO1, and that substitution of four conserved lysine residues disrupts the SUMOylation of SEU, impairs its function in photo- and thermomorphogenesis, and enhances its interaction with PHYTOCHROME-INTERACTING FACTOR 4 transcription factors. Furthermore, the SUMO E3 ligase SIZ1 interacts with SEU and regulates its SUMOylation. Moreover, SEU directly interacts with phytochrome B photoreceptors, and the SUMOylation and stability of SEU are activated by light. Our study reveals a novel post-translational modification mechanism of SEU in which light regulates plant growth and development through SUMOylation-mediated protein stability.
小泛素样修饰物（SUMO）的翻译后修饰（SUMOylation）在调节各种生物过程中起着重要作用；然而，其在植物光信号通路中的功能和调节作用在很大程度上是未知的。SEUSS（SEU）是一种转录共调节剂，它整合了光和温度信号通路，从而调节植物的生长和发育。在这里，我们表明 SEU 是 SUMO1 的底物，并且取代四个保守的赖氨酸残基会破坏 SEU 的 SUMOylation，损害其在光形态发生和热形态发生中的功能，并增强其与 PHYTOCHROME-INTERACTING FACTOR 4 转录因子的相互作用。此外，SUMO E3 连接酶 SIZ1 与 SEU 相互作用并调节其 SUMOylation。此外，SEU 直接与光敏色素 B 光受体相互作用，SEU 的 SUMOylation 和稳定性被光激活。我们的研究揭示了 SEU 的一种新的翻译后修饰机制，其中光通过 SUMOylation 介导的蛋白质稳定性来调节植物的生长和发育。
