YopK regulates the Yersinia pestis type III secretion system from within host cells
Article first published online: 19 JAN 2011
© 2011 Blackwell Publishing Ltd
Volume 79, Issue 6, pages 1445–1461, March 2011
How to Cite
Dewoody, R., Merritt, P. M., Houppert, A. S. and Marketon, M. M. (2011), YopK regulates the Yersinia pestis type III secretion system from within host cells. Molecular Microbiology, 79: 1445–1461. doi: 10.1111/j.1365-2958.2011.07534.x
- Issue published online: 9 MAR 2011
- Article first published online: 19 JAN 2011
- Accepted manuscript online: 4 JAN 2011 12:00AM EST
- Accepted 24 December, 2010.
The pathogenic Yersinia species share a conserved type III secretion system, which delivers cytotoxic effectors known as Yops into target mammalian cells. In all three species, YopK (also called YopQ) plays an important role in regulating this process. In cell culture infections, yopK mutants inject higher levels of Yops, leading to increase cytotoxicity; however, in vivo the same mutants are highly attenuated. In this work, we investigate the mechanism behind this paradox. Using a β-lactamase reporter assay to directly measure the effect of YopK on translocation, we demonstrated that YopK controls the rate of Yop injection. Furthermore, we find that YopK cannot regulate effector Yop translocation from within the bacterial cytosol. YopE is also injected into host cells and was previously shown to contribute to regulation of the injectisome. In this work we show that YopK and YopE work at different steps to regulate Yop injection, with YopK functioning independently of YopE. Finally, by expressing YopK within tissue culture cells, we confirm that YopK regulates translocation from inside the host cell, and we show that cells pre-loaded with YopK are resistant to Yop injection. These results suggest a novel role for YopK in controlling the Yersinia type III secretion system.