Exoproteome Profiling Reveals the Involvement of the Foldase PrsA in the Cell Surface Properties and Pathogenesis of Staphylococcus aureus

Abstract

Staphylococcus aureus is a bacterial pathogen that produces and exports many virulence factors that cause diseases in humans. PrsA, a membrane-bound foldase, is expressed ubiquitously in Gram-positive bacteria and required for the folding of exported proteins into a stable and active structure. To understand the involvement of PrsA in posttranslocational protein folding in S. aureus, a PrsA-deficient mutant of S. aureus HG001 was constructed. Using isobaric tags for relative and absolute quantification (iTRAQ)-based mass spectrometry analyses, the exoproteomes of PrsA mutant and wild type S. aureus were comparatively profiled, and 163 cell wall-associated proteins and 67 exoproteins with altered levels have been identified in the PrsA-deficient mutant. Bioinformatics analyses further reveal that prsA deletion altered the amounts of proteins that are potentially involved in the regulation of cell surface properties and bacterial pathogenesis. To determine the relevancy of our findings, we investigated the functional consequence of prsA deletion in S. aureus. PrsA deficiency can enhance bacterial autoaggregation and increase the adhesion ability of S. aureus to human lung epithelial cells. Moreover, mice infected with PrsA-deficient S. aureus had a better survival rate compared with those infected with the wild-type S. aureus. Collectively, our findings reveal that PrsA is required for the posttranslocational folding of numerous exported proteins and critically affects the cell surface properties and pathogenesis of S. aureus.

PrsA2 (CD630_35000) of Clostridioides difficile Is an Active Parvulin-Type PPIase and a Virulence Modulator

“…PrsA of B. subtilis is important for the secretion of extracellular proteins (Kontinen et al, 1991; Jacobs et al, 1993; Yan and Wu, 2017; Ma et al, 2018). Homologs of PrsA in pathogenic bacteria very often contribute to pathogenicity by the secretion of extracellular virulence factors (Ünal and Steinert, 2014; Jiang et al, 2016; Wiemels et al, 2017; Lin et al, 2018). The most prominent example of these proteins is LmPrsA2 of L. monocytogenes , which has in addition to many other pathogens like S. aureus or Streptococci two homologs of this protein (Cahoon and Freitag, 2014).…”

Involvement of Heme in Colony Spreading of Staphylococcus aureus

“…Phenol soluble modulins were extracted according to a method described previously (Lin et al, 2018). Briefly, an overnight culture was harvested and adjusted with TSB to an OD 578 of 7.0.…”

“…Following centrifugation at 2000 × g for 10 min, the supernatants were separated into two parts. One part of supernatant was used to extract PSMs using a butanol method (Lin et al, 2018). The other part of supernatant was used to isolate the exoproteins using Amicon Ultra-4 centrifugal filters (Millipore, Billerica, MA, United States).…”

Novel Regulation of Alpha-Toxin and the Phenol-Soluble Modulins by Peptidyl-Prolyl cis/trans Isomerase Enzymes in Staphylococcus aureus

“…S. aureus encodes three PPIase enzymes—trigger factor (Tig), PrsA, and PpiB. Recent work in our lab (and others) has demonstrated that both PrsA and PpiB influence the activity of secreted virulence factors [21,22,23].…”

“…A follow-up study demonstrated that PpiB contributes to virulence in a murine abscess model of infection, independently of its PPIase activity [21]. Recently, work by Lin et al on the methicillin-sensitive S. aureus strain HG001, demonstrated that a Δ prsA mutant had better survival than wild-type (WT) in a murine systemic model of infection [22]. They also concluded that there was altered abundance of 67 exoproteins and 163 cell wall-associated proteins in a Δ prsA mutant, including the virulence factors surface protein A (SpA), immunodominant staphylococcal antigen B (IsaB) and the αPSMs.…”