The ubiquitin specific protease USP34 protects the ubiquitin ligase gp78 from proteasomal degradation

Hui Wang; Donghong Ju; Dhong-Hyo Kho; Huanjie Yang; Li Li; Avraham Raz; Fei Sun; Youming Xie

doi:10.1016/j.bbrc.2018.12.141

The ubiquitin specific protease USP34 protects the ubiquitin ligase gp78 from proteasomal degradation

Biochem Biophys Res Commun. 2019 Feb 5;509(2):348-353. doi: 10.1016/j.bbrc.2018.12.141. Epub 2018 Dec 22.

Authors

Hui Wang¹, Donghong Ju², Dhong-Hyo Kho², Huanjie Yang³, Li Li⁴, Avraham Raz⁵, Fei Sun⁶, Youming Xie⁷

Affiliations

¹ Barbara Ann Karmanos Cancer Institute and Department of Oncology, Wayne State University School of Medicine, 421 E Canfield Street, Detroit, MI, 48201, USA; School of Life Science and Technology, Harbin Institute of Technology, Harbin, Heilongjiang Province, 150001, China.
² Barbara Ann Karmanos Cancer Institute and Department of Oncology, Wayne State University School of Medicine, 421 E Canfield Street, Detroit, MI, 48201, USA.
³ School of Life Science and Technology, Harbin Institute of Technology, Harbin, Heilongjiang Province, 150001, China.
⁴ Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI, 48201, USA.
⁵ Barbara Ann Karmanos Cancer Institute and Department of Oncology, Wayne State University School of Medicine, 421 E Canfield Street, Detroit, MI, 48201, USA; Department of Pathology, Wayne State University School of Medicine, Detroit, MI, 48201, USA.
⁶ Department of Physiology, Wayne State University School of Medicine, Detroit, MI, 48201, USA. Electronic address: fsun@med.wayne.edu.
⁷ Barbara Ann Karmanos Cancer Institute and Department of Oncology, Wayne State University School of Medicine, 421 E Canfield Street, Detroit, MI, 48201, USA; Department of Pathology, Wayne State University School of Medicine, Detroit, MI, 48201, USA. Electronic address: xiey@karmanos.org.

PMID: 30585151
DOI: 10.1016/j.bbrc.2018.12.141

Abstract

The E3 ubiquitin (Ub) ligase gp78 plays an important role in endoplasmic reticulum (ER)-associated degradation (ERAD) and regulation of lipid biogenesis. Although a variety of substrates of gp78 have been described, the regulation of the degradation of gp78 itself remains poorly understood. To address this problem, we used co-immunoprecipitation-coupled liquid chromatography-tandem mass spectrometry (Co-IP/LC-MS/MS) to identify novel proteins interacting with gp78. One of the proteins identified in this study is the deubiquitylating (DUB) enzyme USP34 (Ub-specific protease 34). We demonstrate that knockdown of USP34 facilitates proteasomal degradation of gp78 and consequently impairs the function of gp78 in regulating lipid droplet formation. This study unveils a previously unknown function of USP34 in regulating the metabolic stability of gp78 and adds to our understanding of the relevance of partnering of DUBs and E3s in regulation of protein ubiquitylation.

Keywords: Deubiquitylating enzyme; E3 ubiquitin ligase; Protein degradation; USP34; Ubiquitin; gp78.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Cell Line, Tumor
Endoplasmic Reticulum / metabolism
Endoplasmic Reticulum-Associated Degradation*
HEK293 Cells
Hepatocytes / cytology
Hepatocytes / metabolism*
Humans
Lipid Droplets / metabolism
Lipid Metabolism / genetics
Proteasome Endopeptidase Complex / metabolism
Protein Binding
Proteolysis
RNA, Small Interfering / genetics
RNA, Small Interfering / metabolism
Receptors, Autocrine Motility Factor / genetics*
Receptors, Autocrine Motility Factor / metabolism
Signal Transduction
Ubiquitin-Specific Proteases / antagonists & inhibitors
Ubiquitin-Specific Proteases / genetics*
Ubiquitin-Specific Proteases / metabolism
Ubiquitination

Substances

RNA, Small Interfering
AMFR protein, human
Receptors, Autocrine Motility Factor
USP34 protein, human
Ubiquitin-Specific Proteases
Proteasome Endopeptidase Complex