Abstract
Primary response transcription factor, Egr-1, is rapidly activated by a variety of extracellular stimuli. Activation of Egr-1 is shown to function as a master switch activated by ischemia to trigger expression of pivotal regulators of inflammation, coagulation and vascular hyperpermeability. Egr-1 is a short-lived protein, but the mechanism that regulates its stability has not yet been clarified. In this study, the yeast two-hybrid screening revealed that Egr-1 interacts significantly with PRC8 (proteasome component C8) and the specific interaction was confirmed by GST pull-down assay and coimmunoprecipitation. Interestingly, we found that the PRC8-mediated regulation of Egr-1 activity is associated with the proteasome pathway and PRC8 inhibits the transcriptional activity of Egr-1. In addition, Egr-1 protein was specifically multiubiquitinated by ubiquitin. These data strongly imply that Egr-1 protein is targeted for proteolysis by the ubiquitin-dependent proteasome pathway.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Cell Line
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Cysteine Endopeptidases / chemistry
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Cysteine Endopeptidases / metabolism*
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Cysteine Proteinase Inhibitors / pharmacology
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DNA-Binding Proteins / chemistry
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DNA-Binding Proteins / genetics
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DNA-Binding Proteins / metabolism*
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Early Growth Response Protein 1
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Gene Library
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Humans
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Immediate-Early Proteins*
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Leupeptins / pharmacology
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Mice
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Multienzyme Complexes / antagonists & inhibitors
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Multienzyme Complexes / chemistry
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Multienzyme Complexes / metabolism*
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Peptide Hydrolases / chemistry
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Peptide Hydrolases / metabolism
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Proteasome Endopeptidase Complex
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Transcription Factors / chemistry
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Transcription Factors / genetics
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Transcription Factors / metabolism*
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Transcription, Genetic
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Transfection
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Two-Hybrid System Techniques
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Ubiquitin / metabolism
Substances
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Cysteine Proteinase Inhibitors
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DNA-Binding Proteins
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EGR1 protein, human
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Early Growth Response Protein 1
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Egr1 protein, mouse
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Immediate-Early Proteins
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Leupeptins
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Multienzyme Complexes
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Transcription Factors
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Ubiquitin
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Peptide Hydrolases
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Cysteine Endopeptidases
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Proteasome Endopeptidase Complex
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ATP dependent 26S protease
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benzyloxycarbonylleucyl-leucyl-leucine aldehyde