GpsB Promotes PASTA Kinase Signaling and Cephalosporin Resistance in Enterococcus faecalis

Abstract

Enterococci are opportunistic pathogens that can cause severe bacterial infections. Treatment of these infections is challenging because enterococci possess intrinsic and acquired resistance to commonly used antibiotics.

Chromosomal Duplications of MurZ (MurA2) or MurA (MurA1), Amino Acid Substitutions in MurZ (MurA2), and Absence of KhpAB Obviate the Requirement for Protein Phosphorylation inStreptococcus pneumoniaeD39

“…12) (Wamp et al, 2020, Wamp et al, 2022. Recent biochemical studies by Minton and colleagues and by Doubravová and colleagues demonstrate that purified GpsB directly stimulates the activity of the Ser/Thr protein kinases from E. faecalis and S. pneumoniae, respectively (Doubravová, unpublished result) (Minton et al, 2022). In L. monocytogenes, and likely E. faecalis, unphosphorylated ReoM/IreB interacts with the MurA-family enzyme, along with adaptors MurZ and ReoY to present MurA to ClpCP protease for degradation, thereby inhibiting peptidoglycan synthesis and growth (Wamp et al, 2022, Wamp et al, 2020.…”

“…Moreover, the observation that suppression of Δ gpsB is partial, except in phpP suppressors, compared to full suppression of Δ stkP (Table 2; Fig. 4 and S21) is consistent with GpsB having additional regulatory roles in peptidoglycan synthesis (Cleverley et al ., 2019, Hammond et al ., 2022, Minton et al ., 2022, Rued et al ., 2017), besides activating StkP. Importantly, these suppression patterns indicate that regulation of MurZ and MurA is the sole essential requirement for protein phosphorylation in unstressed D39 S. pneumoniae cells growing exponentially in BHI broth.…”

“…The copyright holder for this preprint this version posted March 27, 2023. ; https://doi.org/10.1101/2023.03.26.534294 doi: bioRxiv preprint mutants of Enterococcus faecalis (Efa) also show growth defects at 45°C, but grow normally at 37°C (Minton et al, 2022). In contrast, in derivatives of serotype-2 S. pneumoniae D39 progenitor strains, gpsB is essential at 37°C, and GpsB depletion leads to drastic cell enlargement and elongation, incomplete closure of septal division rings, and eventual cell lysis (Land et al, 2013, Rued et al, 2017.…”

“…In Bacillus subtilis ( Bsu ), Δ gpsB results in growth and morphological abnormality in high salt media and synthetic lethality with Δ ezrA or Δ ftsA (Claessen et al ., 2008), while in Listeria monocytogenes ( Lmo ), Δ gpsB causes marked growth and division defects at 37°C and is lethal at 42°C (Rismondo et al ., 2016). Δ gpsB mutants of Enterococcus faecalis ( Efa ) also show growth defects at 45°C, but grow normally at 37°C (Minton et al ., 2022). In contrast, in derivatives of serotype-2 S. pneumoniae D39 progenitor strains, gpsB is essential at 37°C, and GpsB depletion leads to drastic cell enlargement and elongation, incomplete closure of septal division rings, and eventual cell lysis (Land et al ., 2013, Rued et al ., 2017).…”

“…An additional important regulatory function of GpsB is the maintenance of protein phosphorylation mediated by conserved homologues of serine/threonine kinases, StkP( Spn ), PrkC( Bsu ), and IreK( Efa ) (Rued et al ., 2017, Pompeo et al ., 2015, Fleurie et al ., 2014, Minton et al ., 2022). In S. pneumoniae , phosphorylation of StkP and other StkP substrates is significantly reduced in Δ gpsB mutants of laboratory strains Rx1, R6, or R800 or upon depletion of GpsB in D39-derived strains (Rued et al ., 2017, Fleurie et al ., 2014).…”