Abstract
The glucocorticoid receptor (GR) is a ligand-activated transcription factor that mediates the effects of glucocorticoids in diverse cellular processes, including homeostasis, stress response, and inflammation. Glucocorticoids induce down-regulation of GR at both the mRNA and protein levels, causing reduced hormone responsiveness in response to long-term treatment with glucocorticoid. However, the mechanism involved in this process is still obscure. In this study, we examined whether calpain, a calcium-activated cysteine protease, is involved in ligand-stimulated degradation of GR. In COS-7 cells expressing the human GR, treatment with a calpain inhibitor abolished glucocorticoid-induced down-regulation of GR in a dose dependent manner. The protein level of endogenous GR was also elevated by inhibition of the calpain activity in HeLa cells treated with glucocorticoid. Furthermore, glucocorticoid-induced transcriptional activation of GR was enhanced in cells treated with a calpain inhibitor. These results indicate that calpain is involved in ligand-dependent degradation of GR, thus causing reduced hormone responsiveness.
Original language | English |
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Pages (from-to) | 373-377 |
Number of pages | 5 |
Journal | Biochemical and biophysical research communications |
Volume | 374 |
Issue number | 2 |
DOIs | |
Publication status | Published - 2008 Sept 19 |
Bibliographical note
Funding Information:This work was supported by the Korea Science and Engineering Foundation (KOSEF) Grant funded by the Korea government (MOST) (R01-2007-000-10778-0) and a Grant from the Diseases Network Research Program (M10751050002-07N5105-00210), Ministry of Science and Technology, South Korea.
Keywords
- Calpain
- Dexamethasone
- Glucocorticoid receptor
ASJC Scopus subject areas
- Biophysics
- Biochemistry
- Molecular Biology
- Cell Biology