Endoplasmic reticulum (ER) localization is critical for DsbA-L protein to suppress ER stress and adiponectin down-regulation in adipocytes.
Adiponectin is an adipokine with insulin-sensitizing and anti-inflammatory functions. We previously reported that adiponectin multimerization and stability are promoted by the disulfide bond A oxidoreductase-like protein (DsbA-L) in cells and in vivo. However, the precise mechanism by which DsbA-L regulates adiponectin biosynthesis remains elusive. Here we show that DsbA-L is co-localized with the endoplasmic reticulum (ER) marker protein disulfide isomerase and the mitochondrial marker MitoTracker. In addition, DsbA-L interacts with the ER chaperone protein Ero1-Lα in 3T3-L1 adipocytes. In silico analysis and truncation mapping studies revealed that DsbA-L contains an ER targeting signal at its N terminus. Deletion of the first 6 residues at the N terminus greatly impaired DsbA-L localization in the ER. Overexpression of the wild type but not the ER localization-defective mutant of DsbA-L protects against thapsigargin-induced ER stress and adiponectin down-regulation in 3T3-L1 adipocytes. In addition, overexpression of the wild type but not the ER localization-defective mutant of DsbA-L promotes adiponectin multimerization. Together, our results reveal that DsbA-L is localized in both the mitochondria and the ER in adipocytes and that its ER localization plays a critical role in suppressing ER stress and promoting adiponectin biosynthesis and secretion.
From the Metabolic Syndrome Research Center, the Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China, the Departments of Biochemistry and Molecular Biology, University of New Mexico Health Science Center, Albuquerque, New Mexico 87131.
Meilian
M
Liu
From the Metabolic Syndrome Research Center, the Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China, Biochemistry, and.
Hongzhi
H
Chen
the Departments of Pharmacology, the Department of Endocrinology and Metabolism, Shanghai Diabetes Institute, Shanghai Key Laboratory of Diabetes Mellitus, Shanghai Clinical Center for Diabetes, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200025, China.
Li
L
Wei
the Departments of Pharmacology.
Derong
D
Hu
the Department of Endocrinology and Metabolism, Shanghai Diabetes Institute, Shanghai Key Laboratory of Diabetes Mellitus, Shanghai Clinical Center for Diabetes, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200025, China Cellular and Structural Biology, University of Texas Health Science Center at San Antonio (UTHSCSA), San Antonio, Texas 78229, and.
Kun
K
Dong
the Department of Endocrinology and Metabolism, Shanghai Diabetes Institute, Shanghai Key Laboratory of Diabetes Mellitus, Shanghai Clinical Center for Diabetes, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200025, China.
Weiping
W
Jia
Cellular and Structural Biology, University of Texas Health Science Center at San Antonio (UTHSCSA), San Antonio, Texas 78229, and.
Lily Q
LQ
Dong
From the Metabolic Syndrome Research Center, the Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China, Biochemistry, and the Departments of Pharmacology, LiuF@uthscsa.edu.
Feng
F
Liu
D041721:3T3-L1 Cells; D017667:Adipocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D052242:Adiponectin / Q000235:genetics* / Q000378:metabolism; D000818:Animals; D002454:Cell Differentiation; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism; D059865:Endoplasmic Reticulum Stress / Q000187:drug effects / Q000235:genetics*; D005786:Gene Expression Regulation; D005982:Glutathione Transferase / Q000235:genetics* / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D009154:Mutation; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism; D055503:Protein Multimerization; D015398:Signal Transduction; D019284:Thapsigargin / Q000494:pharmacology
C499918:ADIPOQ protein, human; D052242:Adiponectin; D008562:Membrane Glycoproteins; D019284:Thapsigargin; C405327:ERO1A protein, human; D010088:Oxidoreductases; C487896:GSTK1 protein, human; D005982:Glutathione Transferase
Adiponectin; DsbA-L; ER Localization; Endoplasmic Reticulum (ER); Endoplasmic Reticulum Stress (ER Stress); Endoplasmic Reticulum-associated Protein Degradation (ERAD); Mitochondria