These authors contributed equally to this work.
Mutational dissection of the S/T-kinase StkP reveals crucial roles in cell division of Streptococcus pneumoniae
Article first published online: 11 JAN 2012
© 2011 Blackwell Publishing Ltd
Volume 83, Issue 4, pages 746–758, February 2012
How to Cite
Fleurie, A., Cluzel, C., Guiral, S., Freton, C., Galisson, F., Zanella-Cleon, I., Di Guilmi, A.-M. and Grangeasse, C. (2012), Mutational dissection of the S/T-kinase StkP reveals crucial roles in cell division of Streptococcus pneumoniae. Molecular Microbiology, 83: 746–758. doi: 10.1111/j.1365-2958.2011.07962.x
- Issue published online: 2 FEB 2012
- Article first published online: 11 JAN 2012
- Accepted manuscript online: 28 DEC 2011 04:59PM EST
- Accepted 22 December, 2011.
Eukaryotic-like serine/threonine-kinases are involved in the regulation of a variety of physiological processes in bacteria. In Streptococcus pneumoniae, deletion of the single serine/threonine-kinase gene stkP results in an aberrant cell morphology suggesting that StkP participates in pneumococcus cell division. To understand the function of StkP, we have engineered various pneumococcus strains expressing truncated or kinase-dead forms of StkP. We show that StkP kinase activity, but also its extracellular and cytoplasmic domains per se, are required for pneumococcus cell division. Indeed, we observe that mutant cells show round or elongated shapes with non-functional septa and a chain phenotype, delocalized sites of peptidoglycan synthesis and diffused membrane StkP localization. To gain understanding of the underlying StkP-mediated regulatory mechanism, we show that StkP specifically phosphorylates in vivo the cell division protein DivIVA on threonine 201. Pneumococcus cells expressing non-phosphorylatable DivIVA-T201A possess an elongated shape with a polar bulge and aberrant spatial organization of nascent peptidoglycan. This brings the first evidence of the importance of StkP in relationship to the phosphorylation of one of its substrates in cell division. It is concluded that StkP is a multifunctional protein that plays crucial functions in pneumococcus cell shape and division.