Show simple item record

dc.contributor.authorDent, Alecia T
dc.contributor.authorWilks, Angela
dc.date.accessioned2020-08-06T18:26:40Z
dc.date.available2020-08-06T18:26:40Z
dc.date.issued2020-06-10
dc.identifier.urihttp://hdl.handle.net/10713/13497
dc.description.abstractPseudomonas aeruginosa exhibits a high requirement for iron, which it can acquire via several mechanisms, including the acquisition and utilization of heme. The P. aeruginosa genome encodes two heme uptake systems, the heme assimilation system (Has) and the Pseudomonas heme utilization (Phu) system. Extracellular heme is sensed via the Has system, which encodes an extracytoplasmic function (ECF) σ factor system. Previous studies have shown that the transfer of heme from the extracellular hemophore HasAp to the outer membrane receptor HasR is required for activation of the σ factor HasI and upregulation of has operon expression. Here, employing site-directed mutagenesis, allelic exchange, quantitative PCR analyses, immunoblotting, and 13C-heme uptake experiments, we delineated the differential contributions of the extracellular FRAP/PNPNL loop residue His-624 in HasR and of His-221 in its N-terminal plug domain required for heme capture to heme transport and signaling, respectively. Specifically, we show that substitution of the N-terminal plug His-221 disrupts both signaling and transport, leading to dysregulation of both the Has and Phu uptake systems. Our results are consistent with a model wherein heme release from HasAp to the N-terminal plug of HasR is required to initiate signaling, whereas His-624 is required for simultaneously closing off the heme transport channel from the extracellular medium and triggering heme transport. Our results provide critical insight into heme release, signaling, and transport in P. aeruginosa and suggest a functional link between the ECF σ factor and Phu heme uptake system. © 2020 Dent and Wilks.en_US
dc.description.urihttps://doi.org/10.1074/jbc.RA120.014081en_US
dc.language.isoenen_US
dc.publisherAmerican Society for Biochemistry and Molecular Biology Inc.en_US
dc.relation.ispartofJournal of Biological Chemistryen_US
dc.subjectHasRen_US
dc.subjectPseudomonas heme utilization (Phu)en_US
dc.subjectbacterial signal transductionen_US
dc.subjectbacterial transcriptionen_US
dc.subjectcell surface receptoren_US
dc.subjectcell surface signalingen_US
dc.subjectextracytoplasmic function (ECF)en_US
dc.subjecthemeen_US
dc.subjectheme assimilation systemen_US
dc.subjectheme assimilation system (Has)en_US
dc.subjectheme coordinationen_US
dc.subjectheme uptakeen_US
dc.subjectiron uptakeen_US
dc.subjectouter membraneen_US
dc.subjecttranscriptional activationen_US
dc.titleContributions of the heme coordinating ligands of the outer membrane receptor HasR to extracellular heme sensing and transporten_US
dc.typeArticleen_US
dc.identifier.doi10.1074/jbc.RA120.014081
dc.identifier.pmid32522817
dc.source.volume295
dc.source.issue30
dc.source.beginpage10456
dc.source.endpage10467
dc.source.countryUnited States


This item appears in the following Collection(s)

Show simple item record