Involvement of the Pseudomonas aeruginosa MexAB–OprM efflux pump in the secretion of the metallophore pseudopaline. Issue 1 (23rd September 2020)

• Record Type: Journal Article
• Authors: Gomez, Nicolas Oswaldo; Tetard, Alexandre; Ouerdane, Laurent; Laffont, Clémentine; Brutesco, Catherine; Ball, Geneviève; Lobinski, Ryszard; Denis, Yann; Plésiat, Patrick; Llanes, Catherine; Arnoux, Pascal; Voulhoux, Romé
• Is Part Of: Molecular microbiology. Volume 115:Issue 1(2021)
• Page Start: 84
• Page End: 98
• Publication Date: 2020-09-23
• Subjects: efflux pump -- metallophore -- MexAB–OprM -- Pseudomonasaeruginosa -- pseudopaline; Molecular microbiology -- Periodicals; 572.829
• DOI: 10.1111/mmi.14600
• Languages: English
• ISSNs: 0950-382X

Abstract

Abstract: To overcome the metal restriction imposed by the host's nutritional immunity, pathogenic bacteria use high metal affinity molecules called metallophores. Metallophore‐mediated metal uptake pathways necessitate complex cycles of synthesis, secretion, and recovery of the metallophore across the bacterial envelope. We recently discovered staphylopine and pseudopaline, two members of a new family of broad‐spectrum metallophores important for bacterial survival during infections. Here, we are expending the molecular understanding of the pseudopaline transport cycle across the diderm envelope of the Gram‐negative bacterium Pseudomonas aeruginosa . We first explored pseudopaline secretion by performing in vivo quantifications in various genetic backgrounds and revealed the specific involvement of the MexAB–OprM efflux pump in pseudopaline transport across the outer membrane. We then addressed the recovery part of the cycle by investigating the fate of the recaptured metal‐loaded pseudopaline. To do so, we combined in vitro reconstitution experiments and in vivo phenotyping in absence of pseudopaline transporters to reveal the existence of a pseudopaline modification mechanism, possibly involved in the metal release following pseudopaline recovery. Overall, our data allowed us to provide an improved molecular model of secretion, recovery, and fate of this important metallophore by P. aeruginosa . Abstract : To import metals from low metal environments, bacteria use high affinity molecules called metallophores. Here, we are investigating the secretion and recovery cycle of pseudopaline, a broad spectrum metallophore used by Pseudomonas aeruginosa during infections. Our data revealed the specific involvement of the MexAB‐OprM efflux pump in pseudopaline secretion as well as the existence of an intracellular pseudopaline degradation mechanism providing new clues to the intracellular metal liberation from the imported metal‐pseudopaline complex.