FtsA mutants impaired for self-interaction bypass ZipA suggesting a model in which FtsA's self-interaction competes with its ability to recruit downstream division proteins
Article first published online: 29 NOV 2011
© 2011 Blackwell Publishing Ltd
Volume 83, Issue 1, pages 151–167, January 2012
How to Cite
Pichoff, S., Shen, B., Sullivan, B. and Lutkenhaus, J. (2012), FtsA mutants impaired for self-interaction bypass ZipA suggesting a model in which FtsA's self-interaction competes with its ability to recruit downstream division proteins. Molecular Microbiology, 83: 151–167. doi: 10.1111/j.1365-2958.2011.07923.x
- Issue published online: 20 DEC 2011
- Article first published online: 29 NOV 2011
- Accepted manuscript online: 23 NOV 2011 10:06PM EST
- Accepted 9 November, 2011.
Z-ring assembly requires polymers of the tubulin homologue FtsZ to be tethered to the membrane. Although either ZipA or FtsA is sufficient to do this, both of these are required for recruitment of downstream proteins to form a functional cytokinetic ring. Gain of function mutations in ftsA, such as ftsA* (ftsA-R286W), bypass the requirement for ZipA suggesting that this atypical, well-conserved, actin homologue has a more critical role in Z-ring function. FtsA forms multimers both in vitro and in vivo, but little is known about the role of FtsA polymerization. In this study we identify FtsA mutants impaired for self-interaction. Such mutants are able to support Z-ring assembly and are also able to bypass the requirement for ZipA. These mutants, including FtsA*, have reduced ability to self-interact but interact normally with FtsZ and are less toxic if overexpressed. These results do not support a model in which FtsA monomers antagonize FtsZ polymers. Instead, we propose a new model in which FtsA self-interaction competes with its ability to recruit downstream proteins. In this model FtsA self-interaction at the Z ring is antagonized by ZipA, allowing unpolymerized FtsA to recruit downstream proteins such as FtsN.