Septal secretion of protein A in Staphylococcus aureus requires SecA and lipoteichoic acid synthesis
Abstract
Surface proteins of Staphylococcus aureus are secreted across septal membranes for assembly into the bacterial cross-wall. This localized secretion requires the YSIRK/GXXS motif signal peptide, however the mechanisms supporting precursor trafficking are not known. We show here that the signal peptide of staphylococcal protein A (SpA) is cleaved at the YSIRK/GXXS motif. A SpA signal peptide mutant defective for YSIRK/GXXS cleavage is also impaired for septal secretion and co-purifies with SecA, SecDF and LtaS. SecA depletion blocks precursor targeting to septal membranes, whereas deletion of secDF diminishes SpA secretion into the cross-wall. Depletion of LtaS blocks lipoteichoic acid synthesis and abolishes SpA precursor trafficking to septal membranes. We propose a model whereby SecA directs SpA precursors to lipoteichoic acid-rich septal membranes for YSIRK/GXXS motif cleavage and secretion into the cross-wall.
Data availability
All data generated or analysed during this study are included in the manuscript and supporting files. Source data files have been provided for Figure 2.
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Author details
Funding
National Institute of Allergy and Infectious Diseases (AI038897)
- Olaf Schneewind
Deutsche Forschungsgemeinschaft (YU 181/1-1)
- Wenqi Yu
National Institute of Allergy and Infectious Diseases (AI052474)
- Olaf Schneewind
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2018, Yu et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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