Surface Exposure and Packing of Lipoproteins into Outer Membrane Vesicles Are Coupled Processes in <italic toggle="yes">Bacteroides</italic>

ABSTRACT Outer membrane vesicles (OMVs) are spherical structures derived from the outer membranes (OMs) of Gram-negative bacteria. Bacteroides spp. are prominent components of the human gut microbiota, and OMVs produced by these species are proposed to play key roles in gut homeostasis. OMV biogenes...

Descripción completa

Guardado en:

Detalles Bibliográficos
Autores principales:	Ezequiel Valguarnera, Nichollas E. Scott, Philippe Azimzadeh, Mario F. Feldman
Formato:	article
Lenguaje:	EN
Publicado:	American Society for Microbiology 2018
Materias:	Bacteroides OMV hydrolases lipoproteins vesicles Microbiology QR1-502
Acceso en línea:	https://doaj.org/article/fd89115e51d94a42b4b5a9a9f4b5881f
Etiquetas:	Agregar Etiqueta Sin Etiquetas, Sea el primero en etiquetar este registro!

id	oai:doaj.org-article:fd89115e51d94a42b4b5a9a9f4b5881f
record_format	dspace
spelling	oai:doaj.org-article:fd89115e51d94a42b4b5a9a9f4b5881f2021-11-15T15:22:21ZSurface Exposure and Packing of Lipoproteins into Outer Membrane Vesicles Are Coupled Processes in <italic toggle="yes">Bacteroides</italic>10.1128/mSphere.00559-182379-5042https://doaj.org/article/fd89115e51d94a42b4b5a9a9f4b5881f2018-12-01T00:00:00Zhttps://journals.asm.org/doi/10.1128/mSphere.00559-18https://doaj.org/toc/2379-5042ABSTRACT Outer membrane vesicles (OMVs) are spherical structures derived from the outer membranes (OMs) of Gram-negative bacteria. Bacteroides spp. are prominent components of the human gut microbiota, and OMVs produced by these species are proposed to play key roles in gut homeostasis. OMV biogenesis in Bacteroides is a poorly understood process. Here, we revisited the protein composition of Bacteroides thetaiotaomicron OMVs by mass spectrometry. We confirmed that OMVs produced by this organism contain large quantities of glycosidases and proteases, with most of them being lipoproteins. We found that most of these OMV-enriched lipoproteins are encoded by polysaccharide utilization loci (PULs), such as the sus operon. We examined the subcellular locations of the components of the Sus system and found a split localization; the alpha-amylase SusG is highly enriched in OMVs, while the oligosaccharide importer SusC remains mostly in the OM. We found that all OMV-enriched lipoproteins possess a lipoprotein export sequence (LES), and we show that this signal mediates translocation of SusG from the periplasmic face of the OM toward the extracellular milieu. Mutations in the LES motif caused defects in surface exposure and recruitment of SusG into OMVs. These experiments link, for the first time, surface exposure to recruitment of proteins into OMVs. We also show that surface-exposed SusG in OMVs is active and rescues the growth of bacterial cells incapable of growing on starch as the only carbon source. Our results support the role of OMVs as “public goods” that can be utilized by other organisms with different metabolic capabilities. IMPORTANCE Species from the Bacteroides genus are predominant members of the human gut microbiota. OMVs in Bacteroides have been shown to be important for the homeostasis of complex host-commensal relationships, mainly involving immune tolerance and protection from disease. OMVs carry many enzymatic activities involved in the cleavage of complex polysaccharides and have been proposed as public goods that can provide growth to other bacterial species by release of polysaccharide breakdown products into the gut lumen. This work shows that the presence of a negatively charged rich amino acid motif (LES) is required for efficient packing of the surface-exposed alpha-amylase SusG into OMVs. Our findings strongly suggest that surface exposure is coupled to packing of Bacteroides lipoproteins into OMVs. This is the first step in the generation of tailor-made probiotic interventions that can exploit LES-related sequences to generate Bacteroides strains displaying proteins of interest in OMVs.Ezequiel ValguarneraNichollas E. ScottPhilippe AzimzadehMario F. FeldmanAmerican Society for MicrobiologyarticleBacteroidesOMVhydrolaseslipoproteinsvesiclesMicrobiologyQR1-502ENmSphere, Vol 3, Iss 6 (2018)
institution	DOAJ
collection	DOAJ
language	EN
topic	Bacteroides OMV hydrolases lipoproteins vesicles Microbiology QR1-502
spellingShingle	Bacteroides OMV hydrolases lipoproteins vesicles Microbiology QR1-502 Ezequiel Valguarnera Nichollas E. Scott Philippe Azimzadeh Mario F. Feldman Surface Exposure and Packing of Lipoproteins into Outer Membrane Vesicles Are Coupled Processes in <italic toggle="yes">Bacteroides</italic>
description	ABSTRACT Outer membrane vesicles (OMVs) are spherical structures derived from the outer membranes (OMs) of Gram-negative bacteria. Bacteroides spp. are prominent components of the human gut microbiota, and OMVs produced by these species are proposed to play key roles in gut homeostasis. OMV biogenesis in Bacteroides is a poorly understood process. Here, we revisited the protein composition of Bacteroides thetaiotaomicron OMVs by mass spectrometry. We confirmed that OMVs produced by this organism contain large quantities of glycosidases and proteases, with most of them being lipoproteins. We found that most of these OMV-enriched lipoproteins are encoded by polysaccharide utilization loci (PULs), such as the sus operon. We examined the subcellular locations of the components of the Sus system and found a split localization; the alpha-amylase SusG is highly enriched in OMVs, while the oligosaccharide importer SusC remains mostly in the OM. We found that all OMV-enriched lipoproteins possess a lipoprotein export sequence (LES), and we show that this signal mediates translocation of SusG from the periplasmic face of the OM toward the extracellular milieu. Mutations in the LES motif caused defects in surface exposure and recruitment of SusG into OMVs. These experiments link, for the first time, surface exposure to recruitment of proteins into OMVs. We also show that surface-exposed SusG in OMVs is active and rescues the growth of bacterial cells incapable of growing on starch as the only carbon source. Our results support the role of OMVs as “public goods” that can be utilized by other organisms with different metabolic capabilities. IMPORTANCE Species from the Bacteroides genus are predominant members of the human gut microbiota. OMVs in Bacteroides have been shown to be important for the homeostasis of complex host-commensal relationships, mainly involving immune tolerance and protection from disease. OMVs carry many enzymatic activities involved in the cleavage of complex polysaccharides and have been proposed as public goods that can provide growth to other bacterial species by release of polysaccharide breakdown products into the gut lumen. This work shows that the presence of a negatively charged rich amino acid motif (LES) is required for efficient packing of the surface-exposed alpha-amylase SusG into OMVs. Our findings strongly suggest that surface exposure is coupled to packing of Bacteroides lipoproteins into OMVs. This is the first step in the generation of tailor-made probiotic interventions that can exploit LES-related sequences to generate Bacteroides strains displaying proteins of interest in OMVs.
format	article
author	Ezequiel Valguarnera Nichollas E. Scott Philippe Azimzadeh Mario F. Feldman
author_facet	Ezequiel Valguarnera Nichollas E. Scott Philippe Azimzadeh Mario F. Feldman
author_sort	Ezequiel Valguarnera
title	Surface Exposure and Packing of Lipoproteins into Outer Membrane Vesicles Are Coupled Processes in <italic toggle="yes">Bacteroides</italic>
title_short	Surface Exposure and Packing of Lipoproteins into Outer Membrane Vesicles Are Coupled Processes in <italic toggle="yes">Bacteroides</italic>
title_full	Surface Exposure and Packing of Lipoproteins into Outer Membrane Vesicles Are Coupled Processes in <italic toggle="yes">Bacteroides</italic>
title_fullStr	Surface Exposure and Packing of Lipoproteins into Outer Membrane Vesicles Are Coupled Processes in <italic toggle="yes">Bacteroides</italic>
title_full_unstemmed	Surface Exposure and Packing of Lipoproteins into Outer Membrane Vesicles Are Coupled Processes in <italic toggle="yes">Bacteroides</italic>
title_sort	surface exposure and packing of lipoproteins into outer membrane vesicles are coupled processes in <italic toggle="yes">bacteroides</italic>
publisher	American Society for Microbiology
publishDate	2018
url	https://doaj.org/article/fd89115e51d94a42b4b5a9a9f4b5881f
work_keys_str_mv	AT ezequielvalguarnera surfaceexposureandpackingoflipoproteinsintooutermembranevesiclesarecoupledprocessesinitalictoggleyesbacteroidesitalic AT nichollasescott surfaceexposureandpackingoflipoproteinsintooutermembranevesiclesarecoupledprocessesinitalictoggleyesbacteroidesitalic AT philippeazimzadeh surfaceexposureandpackingoflipoproteinsintooutermembranevesiclesarecoupledprocessesinitalictoggleyesbacteroidesitalic AT marioffeldman surfaceexposureandpackingoflipoproteinsintooutermembranevesiclesarecoupledprocessesinitalictoggleyesbacteroidesitalic
_version_	1718428047897526272

Surface Exposure and Packing of Lipoproteins into Outer Membrane Vesicles Are Coupled Processes in <italic toggle="yes">Bacteroides</italic>

Ejemplares similares