Two Functions of the C-Terminal Domain of Escherichia coli Rob: Mediating 'Sequestration–Dispersal' as a Novel Off–On Switch for Regulating Rob’s Activity as a Transcription Activator and Preventing Degradation of Rob by Lon Protease
| Autor: | Kevin L. Griffith, Edward F. Keen, Richard E. Wolf, M. Megan Fitzpatrick |
|---|---|
| Rok vydání: | 2009 |
| Předmět: |
endocrine system
Protease La Transcription Genetic Pyridines Recombinant Fusion Proteins Biology medicine.disease_cause Models Biological Article chemistry.chemical_compound Genes Reporter Structural Biology Transcription (biology) RNA polymerase Escherichia coli medicine Molecular Biology Cellular localization Regulation of gene expression Escherichia coli Proteins C-terminus fungi Gene Expression Regulation Bacterial Molecular biology Protein Structure Tertiary DNA-Binding Proteins SOXS Regulon Microscopy Fluorescence chemistry Trans-Activators Decanoic Acids |
| Zdroj: | Journal of Molecular Biology. 388:415-430 |
| ISSN: | 0022-2836 |
| DOI: | 10.1016/j.jmb.2009.03.023 |
| Popis: | In Escherichia coli, Rob activates transcription of the SoxRS/MarA/Rob regulon. Previous work revealed that Rob resides in three to four immunostainable foci, that dipyridyl and bile salts are inducers of its activity, and that inducers bind to Rob's C-terminal domain (CTD). We propose that sequestration inactivates Rob by blocking its access to the transcriptional machinery and that inducers activate Rob by mediating its dispersal, allowing interaction with RNA polymerase. To test "sequestration-dispersal" as a new mechanism for regulating the activity of transcriptional activators, we fused Rob's CTD to SoxS and used indirect immunofluorescence microscopy to determine the effect of inducers on SoxS-Rob's cellular localization. Unlike native SoxS, which is uniformly distributed throughout the cell, SoxS-Rob is sequestered without an inducer, but is rapidly dispersed when cells are treated with an inducer. In this manner, Rob's CTD serves as an anti-sigma factor in regulating the co-sigma-factor-like activity of SoxS when fused to it. Rob's CTD also protects its N-terminus from Lon protease, since Lon's normally rapid degradation of SoxS is blocked in the chimera. Accordingly, Rob's CTD has novel regulatory properties that can be bestowed on another E. coli protein. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect