Table S1. Proteins identified to be in greater abundance in WT S. aureus biofilm-

conditioned medium compared to ∆agr biofilm-conditioned medium

Magnitude Category Protein Identity 14.32 Translation RL5 Ribosomal protein 4.73 Translation Syn Asparagine-tRNA 4.09 Translation RL13 Ribosomal protein 3.32 Translation RL332 Ribosomal protein 2.90 Translation EF-TU Elongation factor 2.72 Translation RL27 Ribosomal protein 2.56 Translation GatB Aspartyl/glutamyl-tRNA amidotransferase subunit B 2.42 Translation RS7 Ribosomal protein 2.1 Translation RL16 Ribosomal protein 2.01 Translation RL10 Ribosomal protein 25.93 Metabolism CysK Cysteine synthase 6.92 Metabolism CarB Carbamoyl phosphate synthetase subunit B 4.37 Metabolism OtcC Ornithine carbamoyltransferase 3.91 Metabolism KpyK Pyruvate kinase 3.63 Metabolism Pur8 Adenylosuccinate 3.07 Metabolism HutG Formimidoylglutamase 2.87 Metabolism Pgk Phosphoglycerate kinase 2.50 Metabolism GlmS Glutamine--fructose-6-phosphate aminotransferase 2.42 Metabolism OdpB Pyruvate dehydrogenase E1 component subunit beta 2.29 Metabolism Ldh1 L-lactate dehydrogenase 1 42.01 Protease SplB Serine-like protease a 33.61 Protease SplD Serine-like protease 24.78 Protease SspA Serine protease 24.78 Protease SspB Cysteine protease 14.23 Protease SspP Cysteine protease 9.02 Protease SplA Serine-like protease 6.48 Protease SplC Serine-like protease 2.17 Protease SplE Serine-like protease 11.97 Virulence LukDV/HlgB Leukocidin component 10.59 Virulence HlgA Gamma-hemolysin component A 9.71 Virulence Hld Delta-hemolysin 6.38 Virulence Hla Alpha-hemolysin 5.09 Virulence PsmA4 Phenol-soluble modulin alpha 4 peptide 3.90 Virulence LukB/H Leukocidin component 3.81 Virulence LukA/G Leukocidin component 3.09 Virulence ClfA Clumping factor A 9.98 Cell Stress Asp23 Alkaline shock protein 6.49 Cell Stress Ch60 60 kDa chaperonin 5.92 Cell Stress ClpL ATP-dependent Clp protease ATP-binding subunit 5.08 Cell Stress OhrL Organic hydroperoxide resistance protein-like 2.29 Cell Stress HchA Molecular chaperone Hsp31 and glyoxalase 3 23.69 Other Pnp Polyribonucleotide nucleotidyltransferase 23.39 Other Lip1 Lipase 6.92 Other Pbp Beta-lactam-inducible penicillin-binding protein 6.09 Other PpaC Probable manganese-dependent inorganic pyrophosphatase 5.13 Other Lip2 Lipase 4.33 Other Ggi3 Antibacterial protein 3 homolog 4.25 Other AtpB ATP synthase subunit beta 3.98 Other AtpA ATP synthase subunit alpha 3.84 Other ButA Diacetyl reductase 3.72 Other Ispd2 2-C-methyl-D-erythritol 4-phosphate cytidylyltransferase 2 3.69 Other Y2518 Uncharacterized 3.49 Other Y2365 Uncharacterized lipoprotein 3.44 Other Ptg3C PTS system glucose-specific EIICBA component 3.30 Other GcsT Aminomethyltransferase 3.17 Other FtsZ Cell division 2.94 Other PdxS Pyridoxal biosynthesis lyase 2.83 Other CatA Catalase 2.63 Other Y840 Uncharacterized protein 2.46 Other DldH Dihydrolipoyl dehydrogenase 2.45 Other ClpB Chaperone protein 2.44 Other PtgA Glucose-specific phosphotransferase IIA component 2.36 Other MtlD Mannitol-1-phosphate 5-dehydrogenase 2.21 Other Y370 Uncharacterized protein 2.20 Other Y941 NADH dehydrogenase-like protein 2.16 Other UP355 Uncharacterized protein 2.14 Other Dbh DNA-binding protein 2.10 Other Y1797 Uncharacterized protein aProteins in red were selected for follow-up confirmation with mutant strains