HRD1-mediated ERAD tuning of ER-bound E2 is conserved between plants and mammals.
When membrane proteins and secretory proteins are misfolded or incompletely folded, they are retained in the endoplasmic reticulum (ER) for further folding or degradation. The HMG-COA reductase degradation 1 (HRD1) and degradation of alpha2 10 (DOA10) complexes are two major components involved in the ER-associated protein degradation (ERAD) system in eukaryotic organisms(1-4). However, the relationship between these two complexes is largely unknown, especially in higher eukaryotes. Here, we report that the plant ubiquitin-conjugating enzyme 32 (UBC32), an ER-bound E2 working in the DOA10 complex, is maintained at low levels under standard conditions by proteasome-dependent degradation mediated by the HRD1 complex, the other E3 complex involved in ERAD. Loss of this negative regulation under ER stress increases capacity for degradation of misfolded proteins retained in the ER. Consistently, UBE2J1, the homologue of UBC32 in mammals, was also identified to be targeted by HRD1 for degradation. Taken together, these results suggest that the regulation of UBC32 (or UBE2J1) by the HRD1 complex is conserved between plants and mammals.
State Key Laboratory of Plant Genomics, National Centre for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No. 1 West Beichen Road, Beijing 100101, China.|Graduate University of Chinese Academy of Sciences, Beijing 100049, China.
Qian
Q
Chen
Department of Physiology, Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA.
Yongwang
Y
Zhong
State Key Laboratory of Plant Genomics, National Centre for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No. 1 West Beichen Road, Beijing 100101, China.
Yaorong
Y
Wu
State Key Laboratory of Plant Genomics, National Centre for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No. 1 West Beichen Road, Beijing 100101, China.
Lijing
L
Liu
State Key Laboratory of Plant Genomics, National Centre for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No. 1 West Beichen Road, Beijing 100101, China.|Graduate University of Chinese Academy of Sciences, Beijing 100049, China.
Pengfei
P
Wang
State Key Laboratory of Plant Genomics, National Centre for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No. 1 West Beichen Road, Beijing 100101, China.|Graduate University of Chinese Academy of Sciences, Beijing 100049, China.
Ruijun
R
Liu
State Key Laboratory of Plant Genomics, National Centre for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No. 1 West Beichen Road, Beijing 100101, China.
Feng
F
Cui
State Key Laboratory of Plant Genomics, National Centre for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No. 1 West Beichen Road, Beijing 100101, China.|Graduate University of Chinese Academy of Sciences, Beijing 100049, China.
Qingliang
Q
Li
State Key Laboratory of Plant Genomics, National Centre for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No. 1 West Beichen Road, Beijing 100101, China.
Xiaoyuan
X
Yang
Department of Physiology, Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA.
Shengyun
S
Fang
State Key Laboratory of Plant Genomics, National Centre for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No. 1 West Beichen Road, Beijing 100101, China.|Graduate University of Chinese Academy of Sciences, Beijing 100049, China.
Qi
Q
Xie
D000214:Acyl Coenzyme A / Q000378:metabolism*; D017360:Arabidopsis / Q000254:growth & development / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D060746:Endoplasmic Reticulum-Associated Degradation; D010088:Oxidoreductases / Q000378:metabolism*; D044763:Ubiquitin-Conjugating Enzymes / Q000235:genetics* / Q000378:metabolism
D000214:Acyl Coenzyme A; D029681:Arabidopsis Proteins; C008047:3-hydroxy-3-methylglutaryl-coenzyme A; D010088:Oxidoreductases; C576451:UBC32 protein, Arabidopsis; D044763:Ubiquitin-Conjugating Enzymes