文献类型： 外文期刊

作者： Zhu, Jia-Ying ¹ ; Li, Yuyao ¹ ; Cao, Dong-Mei ² ; Yang, Hongjuan ¹ ; Oh, Eunkyoo ¹ ; Bi, Yang ¹ ; Zhu, Shengwei ¹ ; Wang, ¹ ;

作者机构： 1.Carnegie Inst Sci, Dept Plant Biol, 290 Panama St, Stanford, CA 94305 USA

2.Chinese Acad Sci, Inst Bot, Key Lab Plant Mol Physiol, Beijing 100093, Peoples R China

3.Shanxi Acad Agr Sci, Inst Hort, Taiyuan 030031, Peoples R China

4.Chonnam Natl Univ, Dept Bioenergy Sci & Technol, Gwangju 61186, South Korea

5.Stanford Univ, Dept Biol, Stanford, CA 94305 USA

期刊名称：MOLECULAR CELL （ 影响因子：17.97； 五年影响因子：19.639 ）

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收录情况： SCI

摘要： The glycogen synthase kinase-3 (GSK3) family kinases are central cellular regulators highly conserved in all eukaryotes. In Arabidopsis, the GSK3-like kinase BIN2 phosphorylates a range of proteins to control broad developmental processes, and BIN2 is degraded through unknown mechanism upon receptor kinase-mediated brassinosteroid (BR) signaling. Here we identify KIB1 as an F-box E3 ubiquitin ligase that promotes the degradation of BIN2 while blocking its substrate access. Loss-of-function mutations of KIB1 and its homologs abolished BR-induced BIN2 degradation and caused severe BR-insensitive phenotypes. KIB1 directly interacted with BIN2 in a BR-dependent manner and promoted BIN2 ubiquitination in vitro. Expression of an F-box-truncated KIB1 caused BIN2 accumulation but dephosphorylation of its substrate BZR1 and activation of BR responses because KIB1 blocked BIN2 binding to BZR1. Our study demonstrates that KIB1 plays an essential role in BR signaling by inhibiting BIN2 through dual mechanisms of blocking substrate access and promoting degradation.