The role of proteasome beta subunits in gastrin-mediated transcription of plasminogen activator inhibitor-2 and regenerating protein1.
PLoS One
; 8(3): e59913, 2013.
Article
em En
| MEDLINE
| ID: mdl-23544109
ABSTRACT
The hormone gastrin physiologically regulates gastric acid secretion and also contributes to maintaining gastric epithelial architecture by regulating expression of genes such as plasminogen activator inhibitor 2 (PAI-2) and regenerating protein 1 (Reg1). Here we examine the role of proteasome subunit PSMB1 in the transcriptional regulation of PAI-2 and Reg1 by gastrin, and its subcellular distribution during gastrin stimulation. We used the gastric cancer cell line AGS, permanently transfected with the CCK2 receptor (AGS-GR) to study gastrin stimulated expression of PAI-2 and Reg1 reporter constructs when PSMB1 was knocked down by siRNA. Binding of PSMB1 to the PAI-2 and Reg1 promoters was assessed by chromatin immunoprecipitation (ChIP) assay. Subcellular distribution of PSMB1 was determined by immunocytochemistry and Western Blot. Gastrin robustly increased expression of PAI-2 and Reg1 in AGS-GR cells, but when PSMB1 was knocked down the responses were dramatically reduced. In ChIP assays, following immunoprecipitation of chromatin with a PSMB1 antibody there was a substantial enrichment of DNA from the gastrin responsive regions of the PAI-2 and Reg1 promoters compared with chromatin precipitated with control IgG. In AGS-GR cells stimulated with gastrin there was a significant increase in the ratio of nuclearcytoplasmic PSMB1 over the same timescale as recruitment of PSMB1 to the PAI-2 and Reg1 promoters seen in ChIP assays. We conclude that PSMB1 is part of the transcriptional machinery required for gastrin stimulated expression of PAI-2 and Reg1, and that its change in subcellular distribution in response to gastrin is consistent with this role.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Transcrição Gênica
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Gastrinas
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Inibidor 2 de Ativador de Plasminogênio
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Subunidades Proteicas
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Complexo de Endopeptidases do Proteassoma
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Litostatina
Limite:
Animals
/
Humans
Idioma:
En
Ano de publicação:
2013
Tipo de documento:
Article