Role of Heat Shock Proteases in Quorum-Sensing-Mediated Regulation of Biofilm Formation by <italic toggle="yes">Vibrio</italic> Species

ABSTRACT Capsular polysaccharide (CPS) is essential for the dispersal of biofilms formed by the pathogenic bacterium Vibrio vulnificus. CPS production is induced by the quorum-sensing (QS) master regulator SmcR when biofilms mature. However, V. vulnificus biofilms formed under heat shock conditions...

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Autores principales:	Kyung-Jo Lee, You-Chul Jung, Soon-Jung Park, Kyu-Ho Lee
Formato:	article
Lenguaje:	EN
Publicado:	American Society for Microbiology 2018
Materias:	ClpPA Lon quorum-sensing master regulators Vibrio species Microbiology QR1-502
Acceso en línea:	https://doaj.org/article/d4fd1872f57746efa24c240201854332
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spelling	oai:doaj.org-article:d4fd1872f57746efa24c2402018543322021-11-15T15:53:26ZRole of Heat Shock Proteases in Quorum-Sensing-Mediated Regulation of Biofilm Formation by <italic toggle="yes">Vibrio</italic> Species10.1128/mBio.02086-172150-7511https://doaj.org/article/d4fd1872f57746efa24c2402018543322018-03-01T00:00:00Zhttps://journals.asm.org/doi/10.1128/mBio.02086-17https://doaj.org/toc/2150-7511ABSTRACT Capsular polysaccharide (CPS) is essential for the dispersal of biofilms formed by the pathogenic bacterium Vibrio vulnificus. CPS production is induced by the quorum-sensing (QS) master regulator SmcR when biofilms mature. However, V. vulnificus biofilms formed under heat shock conditions did not exhibit the dispersion stage. Transcripts of the CPS gene cluster were at basal levels in the heat-exposed cell owing to reduced cellular levels of SmcR. At least two proteases induced by heat shock, ClpPA and Lon, were responsible for determining the instability of SmcR. In vitro and in vivo assays demonstrated that SmcR levels were regulated via proteolysis by these proteases, with preferential proteolysis of monomeric SmcR. Thus, CPS production was not induced by QS when bacteria were heat treated. Further studies performed with other Vibrio species demonstrated that high temperature deactivated the QS circuits by increased proteolysis of their QS master regulators, thus resulting in alterations to the QS-regulated phenotypes, including biofilm formation. IMPORTANCE The term "quorum-sensing mechanism" is used to describe diverse bacterial cell density-dependent activities that are achieved by sensing of the signaling molecules and subsequent signal transduction to the master regulators. These well-known bacterial regulatory systems regulate the expression of diverse virulence factors and the construction of biofilms in pathogenic bacteria. There have been numerous studies designed to control bacterial quorum sensing by using small molecules to antagonize the quorum-sensing regulatory components or to interfere with the signaling molecules. In the present study, we showed that the quorum-sensing regulatory circuits of pathogenic Vibrio species were deactivated by heat shock treatment via highly increased proteolysis of the master transcription factors. Our results showed a new mode of quorum deactivation which can be achieved under conditions of high but nonlethal temperature even if the ambient signaling molecules may reach the levels representing high cell density.Kyung-Jo LeeYou-Chul JungSoon-Jung ParkKyu-Ho LeeAmerican Society for MicrobiologyarticleClpPALonquorum-sensing master regulatorsVibrio speciesMicrobiologyQR1-502ENmBio, Vol 9, Iss 1 (2018)
institution	DOAJ
collection	DOAJ
language	EN
topic	ClpPA Lon quorum-sensing master regulators Vibrio species Microbiology QR1-502
spellingShingle	ClpPA Lon quorum-sensing master regulators Vibrio species Microbiology QR1-502 Kyung-Jo Lee You-Chul Jung Soon-Jung Park Kyu-Ho Lee Role of Heat Shock Proteases in Quorum-Sensing-Mediated Regulation of Biofilm Formation by <italic toggle="yes">Vibrio</italic> Species
description	ABSTRACT Capsular polysaccharide (CPS) is essential for the dispersal of biofilms formed by the pathogenic bacterium Vibrio vulnificus. CPS production is induced by the quorum-sensing (QS) master regulator SmcR when biofilms mature. However, V. vulnificus biofilms formed under heat shock conditions did not exhibit the dispersion stage. Transcripts of the CPS gene cluster were at basal levels in the heat-exposed cell owing to reduced cellular levels of SmcR. At least two proteases induced by heat shock, ClpPA and Lon, were responsible for determining the instability of SmcR. In vitro and in vivo assays demonstrated that SmcR levels were regulated via proteolysis by these proteases, with preferential proteolysis of monomeric SmcR. Thus, CPS production was not induced by QS when bacteria were heat treated. Further studies performed with other Vibrio species demonstrated that high temperature deactivated the QS circuits by increased proteolysis of their QS master regulators, thus resulting in alterations to the QS-regulated phenotypes, including biofilm formation. IMPORTANCE The term "quorum-sensing mechanism" is used to describe diverse bacterial cell density-dependent activities that are achieved by sensing of the signaling molecules and subsequent signal transduction to the master regulators. These well-known bacterial regulatory systems regulate the expression of diverse virulence factors and the construction of biofilms in pathogenic bacteria. There have been numerous studies designed to control bacterial quorum sensing by using small molecules to antagonize the quorum-sensing regulatory components or to interfere with the signaling molecules. In the present study, we showed that the quorum-sensing regulatory circuits of pathogenic Vibrio species were deactivated by heat shock treatment via highly increased proteolysis of the master transcription factors. Our results showed a new mode of quorum deactivation which can be achieved under conditions of high but nonlethal temperature even if the ambient signaling molecules may reach the levels representing high cell density.
format	article
author	Kyung-Jo Lee You-Chul Jung Soon-Jung Park Kyu-Ho Lee
author_facet	Kyung-Jo Lee You-Chul Jung Soon-Jung Park Kyu-Ho Lee
author_sort	Kyung-Jo Lee
title	Role of Heat Shock Proteases in Quorum-Sensing-Mediated Regulation of Biofilm Formation by <italic toggle="yes">Vibrio</italic> Species
title_short	Role of Heat Shock Proteases in Quorum-Sensing-Mediated Regulation of Biofilm Formation by <italic toggle="yes">Vibrio</italic> Species
title_full	Role of Heat Shock Proteases in Quorum-Sensing-Mediated Regulation of Biofilm Formation by <italic toggle="yes">Vibrio</italic> Species
title_fullStr	Role of Heat Shock Proteases in Quorum-Sensing-Mediated Regulation of Biofilm Formation by <italic toggle="yes">Vibrio</italic> Species
title_full_unstemmed	Role of Heat Shock Proteases in Quorum-Sensing-Mediated Regulation of Biofilm Formation by <italic toggle="yes">Vibrio</italic> Species
title_sort	role of heat shock proteases in quorum-sensing-mediated regulation of biofilm formation by <italic toggle="yes">vibrio</italic> species
publisher	American Society for Microbiology
publishDate	2018
url	https://doaj.org/article/d4fd1872f57746efa24c240201854332
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Role of Heat Shock Proteases in Quorum-Sensing-Mediated Regulation of Biofilm Formation by <italic toggle="yes">Vibrio</italic> Species

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