Overexpression of the Escherichia coli TolQ protein leads to a null-FtsN-like division phenotype
Article first published online: 2 JUL 2013
© 2013 The Authors. Microbiology Open published by John Wiley & Sons Ltd.
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Volume 2, Issue 4, pages 618–632, August 2013
How to Cite
MicrobiologyOpen 2013; 2(4): 618–632
- Issue published online: 12 AUG 2013
- Article first published online: 2 JUL 2013
- Manuscript Accepted: 3 JUN 2013
- Manuscript Revised: 27 MAY 2013
- Manuscript Received: 27 FEB 2013
- Bowling Green State University
- Lorain County Community College
- Cell division;
- Escherichia coli ;
Mutations involving the Tol-Pal complex of Escherichia coli result in a subtle phenotype in which cells chain when grown under low-salt conditions. Here, the nonpolar deletion of individual genes encoding the cytoplasmic membrane-associated components of the complex (TolQ, TolR, TolA) produced a similar phenotype. Surprisingly, the overexpression of one of these proteins, TolQ, resulted in a much more overt phenotype in which cells occurred as elongated rods coupled in long chains when grown under normal salt conditions. Neither TolR nor TolA overexpression produced a phenotype, nor was the presence of either protein required for the TolQ-dependent phenotype. Consistent with their native membrane topology, the amino-terminal domain of TolQ specifically associated in vivo with the periplasmic domain of FtsN in a cytoplasm-based two-hybrid analysis. Further, the concomitant overexpression of FtsN rescued the TolQ-dependent phenotype, suggesting a model wherein the overexpression of TolQ sequesters FtsN, depleting this essential protein from the divisome during Gram-negative cell division. The role of the Tol-Pal system in division is discussed.