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Regulation of intracellular decorin via proteasome degradation in rat mesangial cells
Author(s) -
Wu Huijuan,
Jiang Weina,
Zhang Yan,
liu Ye,
Zhao Zhonghua,
Guo Muyi,
Ma Duan,
Zhang Zhigang
Publication year - 2010
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.22789
Subject(s) - decorin , mg132 , proteasome inhibitor , tunicamycin , ubiquitin , microbiology and biotechnology , proteasome , immunoprecipitation , cytoplasm , western blot , intracellular , chemistry , ubiquitin ligase , proteoglycan , mesangial cell , biology , biochemistry , endoplasmic reticulum , unfolded protein response , extracellular matrix , gene , in vitro
Decorin (DCN) is a member of small leucine‐rich proteoglycan family that neutralizes the bioactivity of transforming growth factor‐beta1 (TGF‐β1). It has been proven to be a promising anti‐fibrotic agent to treat glomerulonephritis. But the underlining mechanism for regulating and degrading intracellular DCN is still not fully understood. In this study, we investigated the roles of ubiquitination in the regulation of cytoplasmic DCN metabolism in rat mesangial cells (MC) by immunoprecipitation and Western blot. The results showed that a proportion of cytoplasmic DCN was ubiquitinated in normal MC and was enhanced in N ‐glycosylation inhibitor (tunicamycin)‐treated MC. After being treated with the proteasome inhibitor MG132, ubiquitinated DCN accumulated and displayed a prolonged half‐life, accompanied by decreased TGF‐β1 expression and reduced collagen IV mRNA level in MC. This study demonstrated that the stability and function of cytoplasmic DCN can be regulated by ubiquitin‐proteasome system (UPS) in MC, which implies that regulating the ubiquitination and degradation of DCN might be a novel approach for modulating MC bioactivity. J. Cell. Biochem. 111: 1010–1019, 2010. © 2010 Wiley‐Liss, Inc.