Details

Autor(en) / Beteiligte

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

Titel

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

Ist Teil von

• Proceedings of the National Academy of Sciences - PNAS, 2015-09, Vol.112 (39), p.12205-12210

Ort / Verlag

United States: National Acad Sciences

Erscheinungsjahr

2015

Link zum Volltext

Quelle

MEDLINE

Beschreibungen/Notizen

• 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 methanesulfonate-mutagenized brassinosteroid-insensitive 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 HMG-CoA 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.