bioRxiv preprint doi: https://doi.org/10.1101/572172; this version posted February 16, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. 1 The type VII secretion system protects Staphylococcus aureus against 2 antimicrobial host fatty acids 3 Arnaud Kengmo Tchoupa1, Kate E. Watkins1, Rebekah A. Jones1, Agnès Kuroki2, 4 Mohammad Tauqeer Alam1, Sebastien Perrier1,2,3, Yin Chen4, Meera Unnikrishnan1* 5 1Warwick Medical School, University of Warwick, Coventry, United Kingdom 6 2Department of Chemistry, University of Warwick, Coventry, United Kingdom 7 3Faculty of Pharmacy and Pharmaceutical Sciences, Monash University, Parkville, 8 Victoria 3052, Australia 9 4School of Life Sciences, University of Warwick, Coventry, United Kingdom 10 11 Running title: S. aureus T7SS and fatty acid toxicity 12 13 14 15 16 *Corresponding author 17 Email:
[email protected]. 1 bioRxiv preprint doi: https://doi.org/10.1101/572172; this version posted February 16, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. 18 Summary 19 The Staphylococcus aureus type VII secretion system (T7SS) exports several proteins 20 that are pivotal for bacterial virulence. The mechanisms underlying T7SS-mediated 21 staphylococcal survival during infection nevertheless remain unclear. Here we show 22 that the absence of EsxC, a small secreted effector implicated in bacterial persistence, 23 results in cell membrane defects in S.