Ligand-Mediated Biofilm Formation via Enhanced Physical Interaction between a Diguanylate Cyclase and Its Receptor

ABSTRACT The bacterial intracellular second messenger, cyclic dimeric GMP (c-di-GMP), regulates biofilm formation for many bacteria. The binding of c-di-GMP by the inner membrane protein LapD controls biofilm formation, and the LapD receptor is central to a complex network of c-di-GMP-mediated biofi...

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Autores principales:	David Giacalone, T. Jarrod Smith, Alan J. Collins, Holger Sondermann, Lori J. Koziol, George A. O’Toole
Formato:	article
Lenguaje:	EN
Publicado:	American Society for Microbiology 2018
Materias:	CACHE domain Pseudomonas fluorescens biofilm c-di-GMP receptor signaling Microbiology QR1-502
Acceso en línea:	https://doaj.org/article/b5011e19efcc4e4ab6d7916c4423498c
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spelling	oai:doaj.org-article:b5011e19efcc4e4ab6d7916c4423498c2021-11-15T16:00:15ZLigand-Mediated Biofilm Formation via Enhanced Physical Interaction between a Diguanylate Cyclase and Its Receptor10.1128/mBio.01254-182150-7511https://doaj.org/article/b5011e19efcc4e4ab6d7916c4423498c2018-09-01T00:00:00Zhttps://journals.asm.org/doi/10.1128/mBio.01254-18https://doaj.org/toc/2150-7511ABSTRACT The bacterial intracellular second messenger, cyclic dimeric GMP (c-di-GMP), regulates biofilm formation for many bacteria. The binding of c-di-GMP by the inner membrane protein LapD controls biofilm formation, and the LapD receptor is central to a complex network of c-di-GMP-mediated biofilm formation. In this study, we examine how c-di-GMP signaling specificity by a diguanylate cyclase (DGC), GcbC, is achieved via interactions with the LapD receptor and by small ligand sensing via GcbC’s calcium channel chemotaxis (CACHE) domain. We provide evidence that biofilm formation is stimulated by the environmentally relevant organic acid citrate (and a related compound, isocitrate) in a GcbC-dependent manner through enhanced GcbC-LapD interaction, which results in increased LapA localization to the cell surface. Furthermore, GcbC shows little ability to synthesize c-di-GMP in isolation. However, when LapD is present, GcbC activity is significantly enhanced (~8-fold), indicating that engaging the LapD receptor stimulates the activity of this DGC; citrate-enhanced GcbC-LapD interaction further stimulates c-di-GMP synthesis. We propose that the I-site of GcbC serves two roles beyond allosteric control of this enzyme: promoting GcbC-LapD interaction and stabilizing the active conformation of GcbC in the GcbC-LapD complex. Finally, given that LapD can interact with a dozen different DGCs of Pseudomonas fluorescens, many of which have ligand-binding domains, the ligand-mediated enhanced signaling via LapD-GcbC interaction described here is likely a conserved mechanism of signaling in this network. Consistent with this idea, we identify a second example of ligand-mediated enhancement of DGC-LapD interaction that promotes biofilm formation. IMPORTANCE In many bacteria, dozens of enzymes produce the dinucleotide signal c-di-GMP; however, it is unclear how undesired cross talk is mitigated in the context of this soluble signal and how c-di-GMP signaling is regulated by environmental inputs. We demonstrate that GcbC, a DGC, shows little ability to synthesize c-di-GMP in the absence of its cognate receptor LapD; GcbC-LapD interaction enhances c-di-GMP synthesis by GcbC, likely mediated by the I-site of GcbC. We further show evidence for a ligand-mediated mechanism of signaling specificity via increased physical interaction of a DGC with its cognate receptor. We envision a scenario wherein a “cloud” of weakly active DGCs can increase their activity by specific interaction with their receptor in response to appropriate environmental signals, concomitantly boosting c-di-GMP production, ligand-specific signaling, and biofilm formation.David GiacaloneT. Jarrod SmithAlan J. CollinsHolger SondermannLori J. KoziolGeorge A. O’TooleAmerican Society for MicrobiologyarticleCACHE domainPseudomonas fluorescensbiofilmc-di-GMPreceptorsignalingMicrobiologyQR1-502ENmBio, Vol 9, Iss 4 (2018)
institution	DOAJ
collection	DOAJ
language	EN
topic	CACHE domain Pseudomonas fluorescens biofilm c-di-GMP receptor signaling Microbiology QR1-502
spellingShingle	CACHE domain Pseudomonas fluorescens biofilm c-di-GMP receptor signaling Microbiology QR1-502 David Giacalone T. Jarrod Smith Alan J. Collins Holger Sondermann Lori J. Koziol George A. O’Toole Ligand-Mediated Biofilm Formation via Enhanced Physical Interaction between a Diguanylate Cyclase and Its Receptor
description	ABSTRACT The bacterial intracellular second messenger, cyclic dimeric GMP (c-di-GMP), regulates biofilm formation for many bacteria. The binding of c-di-GMP by the inner membrane protein LapD controls biofilm formation, and the LapD receptor is central to a complex network of c-di-GMP-mediated biofilm formation. In this study, we examine how c-di-GMP signaling specificity by a diguanylate cyclase (DGC), GcbC, is achieved via interactions with the LapD receptor and by small ligand sensing via GcbC’s calcium channel chemotaxis (CACHE) domain. We provide evidence that biofilm formation is stimulated by the environmentally relevant organic acid citrate (and a related compound, isocitrate) in a GcbC-dependent manner through enhanced GcbC-LapD interaction, which results in increased LapA localization to the cell surface. Furthermore, GcbC shows little ability to synthesize c-di-GMP in isolation. However, when LapD is present, GcbC activity is significantly enhanced (~8-fold), indicating that engaging the LapD receptor stimulates the activity of this DGC; citrate-enhanced GcbC-LapD interaction further stimulates c-di-GMP synthesis. We propose that the I-site of GcbC serves two roles beyond allosteric control of this enzyme: promoting GcbC-LapD interaction and stabilizing the active conformation of GcbC in the GcbC-LapD complex. Finally, given that LapD can interact with a dozen different DGCs of Pseudomonas fluorescens, many of which have ligand-binding domains, the ligand-mediated enhanced signaling via LapD-GcbC interaction described here is likely a conserved mechanism of signaling in this network. Consistent with this idea, we identify a second example of ligand-mediated enhancement of DGC-LapD interaction that promotes biofilm formation. IMPORTANCE In many bacteria, dozens of enzymes produce the dinucleotide signal c-di-GMP; however, it is unclear how undesired cross talk is mitigated in the context of this soluble signal and how c-di-GMP signaling is regulated by environmental inputs. We demonstrate that GcbC, a DGC, shows little ability to synthesize c-di-GMP in the absence of its cognate receptor LapD; GcbC-LapD interaction enhances c-di-GMP synthesis by GcbC, likely mediated by the I-site of GcbC. We further show evidence for a ligand-mediated mechanism of signaling specificity via increased physical interaction of a DGC with its cognate receptor. We envision a scenario wherein a “cloud” of weakly active DGCs can increase their activity by specific interaction with their receptor in response to appropriate environmental signals, concomitantly boosting c-di-GMP production, ligand-specific signaling, and biofilm formation.
format	article
author	David Giacalone T. Jarrod Smith Alan J. Collins Holger Sondermann Lori J. Koziol George A. O’Toole
author_facet	David Giacalone T. Jarrod Smith Alan J. Collins Holger Sondermann Lori J. Koziol George A. O’Toole
author_sort	David Giacalone
title	Ligand-Mediated Biofilm Formation via Enhanced Physical Interaction between a Diguanylate Cyclase and Its Receptor
title_short	Ligand-Mediated Biofilm Formation via Enhanced Physical Interaction between a Diguanylate Cyclase and Its Receptor
title_full	Ligand-Mediated Biofilm Formation via Enhanced Physical Interaction between a Diguanylate Cyclase and Its Receptor
title_fullStr	Ligand-Mediated Biofilm Formation via Enhanced Physical Interaction between a Diguanylate Cyclase and Its Receptor
title_full_unstemmed	Ligand-Mediated Biofilm Formation via Enhanced Physical Interaction between a Diguanylate Cyclase and Its Receptor
title_sort	ligand-mediated biofilm formation via enhanced physical interaction between a diguanylate cyclase and its receptor
publisher	American Society for Microbiology
publishDate	2018
url	https://doaj.org/article/b5011e19efcc4e4ab6d7916c4423498c
work_keys_str_mv	AT davidgiacalone ligandmediatedbiofilmformationviaenhancedphysicalinteractionbetweenadiguanylatecyclaseanditsreceptor AT tjarrodsmith ligandmediatedbiofilmformationviaenhancedphysicalinteractionbetweenadiguanylatecyclaseanditsreceptor AT alanjcollins ligandmediatedbiofilmformationviaenhancedphysicalinteractionbetweenadiguanylatecyclaseanditsreceptor AT holgersondermann ligandmediatedbiofilmformationviaenhancedphysicalinteractionbetweenadiguanylatecyclaseanditsreceptor AT lorijkoziol ligandmediatedbiofilmformationviaenhancedphysicalinteractionbetweenadiguanylatecyclaseanditsreceptor AT georgeaotoole ligandmediatedbiofilmformationviaenhancedphysicalinteractionbetweenadiguanylatecyclaseanditsreceptor
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Ligand-Mediated Biofilm Formation via Enhanced Physical Interaction between a Diguanylate Cyclase and Its Receptor

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