The Escherichia coli adherence factor plasmid of enteropathogenic Escherichia coli causes a global decrease in ubiquitylated host cell proteins by decreasing ubiquitin E1 enzyme expression through host aspartyl proteases
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| Authors: | Lin, AE; Guttman, JA |
| Year: | 2012 |
| Journal: | International Journal of Biochemistry & Cell Biology 44: 2223-2232 Article Link (DOI) |
| Title: | The Escherichia coli adherence factor plasmid of enteropathogenic Escherichia coli causes a global decrease in ubiquitylated host cell proteins by decreasing ubiquitin E1 enzyme expression through host aspartyl proteases |
| Abstract: | Ubiquitylation is a widespread post-translational global regulatory system that is essential for the proper functioning of various cellular events. Recent studies have shown that certain types of Escherichia coil can exploit specific aspects of the ubiquitylation system to influence downstream targets. Despite these findings, examination of the effects pathogenic E. coli have on the overall host ubiquitylation system remain unexplored. To study the impact that pathogenic E. coli have on the ubiquitylation levels of host proteins during infections, we analyzed the entire ubiquitylation system during enteropathogenic E. coil infections of cultured cells. We found that these microbes caused a dramatic decrease in ubiquitylated host proteins during these infections. This occurred with a concomitant reduction in the expression of essential El activating enzymes in the host, which are integral for the initiation of the ubiquitylation cascade. Control of host El enzyme levels was dependent on the E. coli adherence factor plasmid which acted on host aspartyl proteases within enteropathogenic E. coil. Hijacking of the ubiquitylation system did not require the plasmid-encoded regulator or bundle forming pilus expression, as enteropathogenic E. coil mutated in those factors did not revert the ubiquitylation of host proteins or the abundance of El enzyme proteins to uninfected levels. Our work shows that E. coil have developed strategies to usurp post-translational systems by targeting crucial enzymes. The ability of enteropathogenic E. coil to inactivate host protein ubiquitylation could enable more efficient effector protein functionality, providing increased bacterial control of host cells during enteropathogenic E. coil pathogenesis. (C) 2012 Elsevier Ltd. All rights reserved. |
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