The F-box Protein KIB1 Mediates Brassinosteroid-Induced Inactivation and Degradation of GSK3-like Kinases in Arabidopsis.
Mol Cell
; 66(5): 648-657.e4, 2017 Jun 01.
Article
em En
| MEDLINE
| ID: mdl-28575660
ABSTRACT
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.
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Texto completo:
1
Bases de dados:
MEDLINE
Assunto principal:
Reguladores de Crescimento de Plantas
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Proteínas Quinases
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Esteroides Heterocíclicos
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Plantas Geneticamente Modificadas
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Arabidopsis
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Proteínas de Arabidopsis
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Quinase 3 da Glicogênio Sintase
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Ubiquitina-Proteína Ligases
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Proteínas F-Box
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Brassinosteroides
Idioma:
En
Revista:
Mol Cell
Assunto da revista:
BIOLOGIA MOLECULAR
Ano de publicação:
2017
Tipo de documento:
Article
País de afiliação:
Estados Unidos