Glycogen synthase kinase 3 (GSK3) proteins play key roles in brassinosteroid (BR) signaling during plant growth and development by phosphorylating various substrates. However, how GSK3 protein stability and activity are themselves modulated is not well understood. Here, we demonstrate in vitro and in vivo that C-TERMINAL DOMAIN PHOSPHATASE-LIKE 3 (OsCPL3), a member of the RNA Pol Ⅱ CTD phosphatase-like family, physically inter-acts with OsGSK2 in rice (Oryza sativa). OsCPL3 expression was widely detected in various tis-sues and organs including roots, leaves and lamina joints, and was induced by exogenous BR treatment. OsCPL3 localized to the nucleus, where it dephosphorylated OsGSK2 at the Ser-222 and Thr-284 residues to modulate its protein turnover and kinase activity, in turn affecting the degradation of BRASSINAZOLE-RESISTANT 1 (BZR1) and BR signaling. Loss of OsCPL3 function resulted in higher OsGSK2 abundance and lower OsBZR1 levels, leading to decreased BR responsiveness and alterations in plant morphology including semi-dwarfism, leaf erectness and grain size, which are of fun-damental importance to crop productivity. These results reveal a previously unrecognized role for OsCPL3 and add another layer of com-plexity to the tightly controlled BR signaling pathway in plants.

Luping Gong;Shenghao Liao;Wen Duan;Yongqiang Liu;Dongmei Zhu;Xiaosheng Zhou;Baoping Xue;Chengcai Chu;Yun-Kuan Liang

State Key Laboratory of Hybrid Rice,Department of Plant Sciences,College of Life Sciences,Wuhan University,Wuhan 430072,China;State Key Laboratory of Plant Genomics,Institute of Genetics and Developmental Biology,the Innovative Academy for Seed Design,Chinese Academy of Sciences,Beijing 100101,China;Hubei Hongshan Laboratory,Wuhan 430070,China

植物学报（英文版）

[1]Luping Gong;Shenghao Liao;Wen Duan;Yongqiang Liu;Dongmei Zhu;Xiaosheng Zhou;Baoping Xue;Chengcai Chu;Yun-Kuan Liang-.OsCPL3 is involved in brassinosteroid signaling by regulating OsGSK2 stability)[J].植物学报（英文版）,2022(08):1560-1574

OsCPL3,OsGSK2,PHOSPHATASE,dephosphorylated,BRASSINAZOLE,RESISTANT,OsBZR1,erectness

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