EBS7 is a plant-specific component of a highly conserved endoplasmic reticulum-associated degradation system in Arabidopsis

Yidan Liu, Congcong Zhang, Dinghe Wang, Wei Su, Linchuan Liu, Muyang Wang, Jianming Li*

*Corresponding author for this work

Research output: Contribution to journalJournal articlepeer-review

49 Citations (Scopus)

Abstract

Endoplasmic reticulum (ER)-associated degradation (ERAD) is an essential part of an ER-localized protein quality-control system for eliminating terminally misfolded proteins. Recent studies have demonstrated that the ERAD machinery is conserved among yeast, animals, and plants; however, it remains unknown if the plant ERAD system involves plant-specific components. Here we report that the Arabidopsis ethyl methane sulfonate-mutagenized brassinosteroidin sensitive 1 suppressor 7 (EBS7) gene encodes an ER membrane localized ERAD component that is highly conserved in land plants. Loss-of-function ebs7 mutations prevent ERAD of brassinosteroid insensitive 1-9 (bri1-9) and bri1-5, two ER-retained mutant variants of the cell-surface receptor for brassinosteroids (BRs). As a result, the two mutant receptors accumulate in the ER and consequently leak to the plasma membrane, resulting in the restoration of BR sensitivity and phenotypic suppression of the bri1-9 and bri1-5 mutants. EBS7 accumulates under ER stress, and its mutations lead to hypersensitivity to ER and salt stresses. EBS7 interacts with the ER membrane-anchored ubiquitin ligase Arabidopsis thaliana HMGCoA reductase degradation 1a (AtHrd1a), one of the central components of the Arabidopsis ERAD machinery, and an ebs7 mutation destabilizes AtHrd1a to reduce polyubiquitination of bri1-9. Taken together, our results uncover a plant-specific component of a plant ERAD pathway and also suggest its likely biochemical function.

Original languageEnglish
Pages (from-to)12205-12210
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume112
Issue number39
Early online date14 Sept 2015
DOIs
Publication statusPublished - 29 Sept 2015

Scopus Subject Areas

  • General

User-Defined Keywords

  • Brassinosteroid receptor BRI1
  • EMS-mutagenized bri1 suppressor
  • ERAD
  • Ubiquitin ligase E3
  • Unfolded protein response

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