TOPP4 regulates the stability of Phytochrome Interacting Factor 5 during photomorphogenesis in Arabidopsis
TOPP4 regulates the stability of Phytochrome Interacting Factor 5 during photomorphogenesis in Arabidopsis
复制标题
TOPP4 调节拟南芥光形态发生过程中光敏色素相互作用因子 5 的稳定性
DOI：
10.1104/pp.15.01729
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发表时间：
2016
期刊：
影响因子：
7.4
通讯作者：
Hou Suiwen
中科院分区：
文献类型：
--
作者：
Yue Jing;Qin Qianqian;Meng Siyuan;Jin Huiting;Gou Xiaoping;Li Jia;Hou Suiwen
In plants, photoreceptors transfer light signals to phytochrome-interacting factors (PIFs), inducing the rapid phosphorylation and degradation of PIFs to promote photomorphogenesis. However, the phosphatase responsible for PIF dephosphorylation remains unknown. In this study, we identified a type 1 protein phosphatase, TOPP4, that is essential for PIF5 protein stability in Arabidopsis (Arabidopsis thaliana). Compared with the wild type, the dominant-negative mutant,topp4-1, displayed reduced hypocotyl length and larger apical hook and cotyledon opening angle under red light. Overexpression oftopp4-1in the wild type led to defects that were similar to those in thetopp4-1mutant. Red light induced phytochrome B (phyB)-dependentTOPP4expression in hypocotyls. Thetopp4-1mutation weakened the closed cotyledon angle ofphyB-9andphyA-211 phyB-9, while overexpression ofTOPP4significantly repressed the short hypocotyls of phyB-green fluorescent protein seedlings, indicating that TOPP4 and phyB function in an antagonistic way during photomorphogenesis. Protein interaction assays and phosphorylation studies demonstrate that TOPP4 interacts directly with PIF5 and dephosphorylates it. Furthermore, TOPP4 inhibits the red light-induced ubiquitination and degradation of PIF5. These findings demonstrate that dephosphorylation of PIF5 by TOPP4 inhibits its ubiquitin-mediated degradation during photomorphogenesis. These data outline a novel phytochrome signaling mechanism by which TOPP4-mediated dephosphorylation of PIF5 attenuates phytochrome-dependent light responses.
