High-Resolution pH Imaging of Living Bacterial Cells To Detect Local pH Differences

ABSTRACT Protons are utilized for various biological activities such as energy transduction and cell signaling. For construction of the bacterial flagellum, a type III export apparatus utilizes ATP and proton motive force to drive flagellar protein export, but the energy transduction mechanism remai...

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Autores principales:	Yusuke V. Morimoto, Nobunori Kami-ike, Tomoko Miyata, Akihiro Kawamoto, Takayuki Kato, Keiichi Namba, Tohru Minamino
Formato:	article
Lenguaje:	EN
Publicado:	American Society for Microbiology 2016
Materias:	Microbiology QR1-502
Acceso en línea:	https://doaj.org/article/50902300b9c1415598037e6fa690fa2d
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spelling	oai:doaj.org-article:50902300b9c1415598037e6fa690fa2d2021-11-15T15:50:15ZHigh-Resolution pH Imaging of Living Bacterial Cells To Detect Local pH Differences10.1128/mBio.01911-162150-7511https://doaj.org/article/50902300b9c1415598037e6fa690fa2d2016-12-01T00:00:00Zhttps://journals.asm.org/doi/10.1128/mBio.01911-16https://doaj.org/toc/2150-7511ABSTRACT Protons are utilized for various biological activities such as energy transduction and cell signaling. For construction of the bacterial flagellum, a type III export apparatus utilizes ATP and proton motive force to drive flagellar protein export, but the energy transduction mechanism remains unclear. Here, we have developed a high-resolution pH imaging system to measure local pH differences within living Salmonella enterica cells, especially in close proximity to the cytoplasmic membrane and the export apparatus. The local pH near the membrane was ca. 0.2 pH unit higher than the bulk cytoplasmic pH. However, the local pH near the export apparatus was ca. 0.1 pH unit lower than that near the membrane. This drop of local pH depended on the activities of both transmembrane export components and FliI ATPase. We propose that the export apparatus acts as an H+/protein antiporter to couple ATP hydrolysis with H+ flow to drive protein export. IMPORTANCE The flagellar type III export apparatus is required for construction of the bacterial flagellum beyond the cellular membranes. The export apparatus consists of a transmembrane export gate and a cytoplasmic ATPase complex. The export apparatus utilizes ATP and proton motive force as the energy source for efficient and rapid protein export during flagellar assembly, but it remains unknown how. In this study, we have developed an in vivo pH imaging system with high spatial and pH resolutions with a pH indicator probe to measure local pH near the export apparatus. We provide direct evidence suggesting that ATP hydrolysis by the ATPase complex and the following rapid protein translocation by the export gate are both linked to efficient proton translocation through the gate.Yusuke V. MorimotoNobunori Kami-ikeTomoko MiyataAkihiro KawamotoTakayuki KatoKeiichi NambaTohru MinaminoAmerican Society for MicrobiologyarticleMicrobiologyQR1-502ENmBio, Vol 7, Iss 6 (2016)
institution	DOAJ
collection	DOAJ
language	EN
topic	Microbiology QR1-502
spellingShingle	Microbiology QR1-502 Yusuke V. Morimoto Nobunori Kami-ike Tomoko Miyata Akihiro Kawamoto Takayuki Kato Keiichi Namba Tohru Minamino High-Resolution pH Imaging of Living Bacterial Cells To Detect Local pH Differences
description	ABSTRACT Protons are utilized for various biological activities such as energy transduction and cell signaling. For construction of the bacterial flagellum, a type III export apparatus utilizes ATP and proton motive force to drive flagellar protein export, but the energy transduction mechanism remains unclear. Here, we have developed a high-resolution pH imaging system to measure local pH differences within living Salmonella enterica cells, especially in close proximity to the cytoplasmic membrane and the export apparatus. The local pH near the membrane was ca. 0.2 pH unit higher than the bulk cytoplasmic pH. However, the local pH near the export apparatus was ca. 0.1 pH unit lower than that near the membrane. This drop of local pH depended on the activities of both transmembrane export components and FliI ATPase. We propose that the export apparatus acts as an H+/protein antiporter to couple ATP hydrolysis with H+ flow to drive protein export. IMPORTANCE The flagellar type III export apparatus is required for construction of the bacterial flagellum beyond the cellular membranes. The export apparatus consists of a transmembrane export gate and a cytoplasmic ATPase complex. The export apparatus utilizes ATP and proton motive force as the energy source for efficient and rapid protein export during flagellar assembly, but it remains unknown how. In this study, we have developed an in vivo pH imaging system with high spatial and pH resolutions with a pH indicator probe to measure local pH near the export apparatus. We provide direct evidence suggesting that ATP hydrolysis by the ATPase complex and the following rapid protein translocation by the export gate are both linked to efficient proton translocation through the gate.
format	article
author	Yusuke V. Morimoto Nobunori Kami-ike Tomoko Miyata Akihiro Kawamoto Takayuki Kato Keiichi Namba Tohru Minamino
author_facet	Yusuke V. Morimoto Nobunori Kami-ike Tomoko Miyata Akihiro Kawamoto Takayuki Kato Keiichi Namba Tohru Minamino
author_sort	Yusuke V. Morimoto
title	High-Resolution pH Imaging of Living Bacterial Cells To Detect Local pH Differences
title_short	High-Resolution pH Imaging of Living Bacterial Cells To Detect Local pH Differences
title_full	High-Resolution pH Imaging of Living Bacterial Cells To Detect Local pH Differences
title_fullStr	High-Resolution pH Imaging of Living Bacterial Cells To Detect Local pH Differences
title_full_unstemmed	High-Resolution pH Imaging of Living Bacterial Cells To Detect Local pH Differences
title_sort	high-resolution ph imaging of living bacterial cells to detect local ph differences
publisher	American Society for Microbiology
publishDate	2016
url	https://doaj.org/article/50902300b9c1415598037e6fa690fa2d
work_keys_str_mv	AT yusukevmorimoto highresolutionphimagingoflivingbacterialcellstodetectlocalphdifferences AT nobunorikamiike highresolutionphimagingoflivingbacterialcellstodetectlocalphdifferences AT tomokomiyata highresolutionphimagingoflivingbacterialcellstodetectlocalphdifferences AT akihirokawamoto highresolutionphimagingoflivingbacterialcellstodetectlocalphdifferences AT takayukikato highresolutionphimagingoflivingbacterialcellstodetectlocalphdifferences AT keiichinamba highresolutionphimagingoflivingbacterialcellstodetectlocalphdifferences AT tohruminamino highresolutionphimagingoflivingbacterialcellstodetectlocalphdifferences
_version_	1718427456787972096

High-Resolution pH Imaging of Living Bacterial Cells To Detect Local pH Differences

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