Involvement of FtsE ATPase and FtsX Extracellular Loops 1 and 2 in FtsEX-PcsB Complex Function in Cell Division of <named-content content-type="genus-species">Streptococcus pneumoniae</named-content> D39

ABSTRACT The FtsEX protein complex has recently been proposed to play a major role in coordinating peptidoglycan (PG) remodeling by hydrolases with the division of bacterial cells. According to this model, cytoplasmic FtsE ATPase interacts with the FtsZ divisome and FtsX integral membrane protein an...

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Autores principales:	Lok-To Sham, Katelyn R. Jensen, Kevin E. Bruce, Malcolm E. Winkler
Formato:	article
Lenguaje:	EN
Publicado:	American Society for Microbiology 2013
Materias:	Microbiology QR1-502
Acceso en línea:	https://doaj.org/article/7a3b2381d75c40778e334566d4e79b94
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spelling	oai:doaj.org-article:7a3b2381d75c40778e334566d4e79b942021-11-15T15:43:08ZInvolvement of FtsE ATPase and FtsX Extracellular Loops 1 and 2 in FtsEX-PcsB Complex Function in Cell Division of <named-content content-type="genus-species">Streptococcus pneumoniae</named-content> D3910.1128/mBio.00431-132150-7511https://doaj.org/article/7a3b2381d75c40778e334566d4e79b942013-08-01T00:00:00Zhttps://journals.asm.org/doi/10.1128/mBio.00431-13https://doaj.org/toc/2150-7511ABSTRACT The FtsEX protein complex has recently been proposed to play a major role in coordinating peptidoglycan (PG) remodeling by hydrolases with the division of bacterial cells. According to this model, cytoplasmic FtsE ATPase interacts with the FtsZ divisome and FtsX integral membrane protein and powers allosteric activation of an extracellular hydrolase interacting with FtsX. In the major human respiratory pathogen Streptococcus pneumoniae (pneumococcus), a large extracellular-loop domain of FtsX (ECL1FtsX) is thought to interact with the coiled-coil domain of the PcsB protein, which likely functions as a PG amidase or endopeptidase required for normal cell division. This paper provides evidence for two key tenets of this model. First, we show that FtsE protein is essential, that depletion of FtsE phenocopies cell defects caused by depletion of FtsX or PcsB, and that changes of conserved amino acids in the FtsE ATPase active site are not tolerated. Second, we show that temperature-sensitive (Ts) pcsB mutations resulting in amino acid changes in the PcsB coiled-coil domain (CCPcsB) are suppressed by ftsX mutations resulting in amino acid changes in the distal part of ECL1FtsX or in a second, small extracellular-loop domain (ECL2FtsX). Some FtsX suppressors are allele specific for changes in CCPcsB, and no FtsX suppressors were found for amino acid changes in the catalytic PcsB CHAP domain (CHAPPcsB). These results strongly support roles for both ECL1FtsX and ECL2FtsX in signal transduction to the coiled-coil domain of PcsB. Finally, we found that pcsBCC(Ts) mutants (Ts mutants carrying mutations in the region of pcsB corresponding to the coiled-coil domain) unexpectedly exhibit delayed stationary-phase autolysis at a permissive growth temperature. IMPORTANCE Little is known about how FtsX interacts with cognate PG hydrolases in any bacterium, besides that ECL1FtsX domains somehow interact with coiled-coil domains. This work used powerful genetic approaches to implicate a specific region of pneumococcal ECL1FtsX and the small ECL2FtsX in the interaction with CCPcsB. These findings identify amino acids important for in vivo signal transduction between FtsX and PcsB for the first time. This paper also supports the central hypothesis that signal transduction between pneumococcal FtsX and PcsB is linked to ATP hydrolysis by essential FtsE, which couples PG hydrolysis to cell division. The classical genetic approaches used here can be applied to dissect interactions of other integral membrane proteins involved in PG biosynthesis. Finally, delayed autolysis of the pcsBCC(Ts) mutants suggests that the FtsEX-PcsB PG hydrolase may generate a signal in the PG necessary for activation of the major LytA autolysin as pneumococcal cells enter stationary phase.Lok-To ShamKatelyn R. JensenKevin E. BruceMalcolm E. WinklerAmerican Society for MicrobiologyarticleMicrobiologyQR1-502ENmBio, Vol 4, Iss 4 (2013)
institution	DOAJ
collection	DOAJ
language	EN
topic	Microbiology QR1-502
spellingShingle	Microbiology QR1-502 Lok-To Sham Katelyn R. Jensen Kevin E. Bruce Malcolm E. Winkler Involvement of FtsE ATPase and FtsX Extracellular Loops 1 and 2 in FtsEX-PcsB Complex Function in Cell Division of <named-content content-type="genus-species">Streptococcus pneumoniae</named-content> D39
description	ABSTRACT The FtsEX protein complex has recently been proposed to play a major role in coordinating peptidoglycan (PG) remodeling by hydrolases with the division of bacterial cells. According to this model, cytoplasmic FtsE ATPase interacts with the FtsZ divisome and FtsX integral membrane protein and powers allosteric activation of an extracellular hydrolase interacting with FtsX. In the major human respiratory pathogen Streptococcus pneumoniae (pneumococcus), a large extracellular-loop domain of FtsX (ECL1FtsX) is thought to interact with the coiled-coil domain of the PcsB protein, which likely functions as a PG amidase or endopeptidase required for normal cell division. This paper provides evidence for two key tenets of this model. First, we show that FtsE protein is essential, that depletion of FtsE phenocopies cell defects caused by depletion of FtsX or PcsB, and that changes of conserved amino acids in the FtsE ATPase active site are not tolerated. Second, we show that temperature-sensitive (Ts) pcsB mutations resulting in amino acid changes in the PcsB coiled-coil domain (CCPcsB) are suppressed by ftsX mutations resulting in amino acid changes in the distal part of ECL1FtsX or in a second, small extracellular-loop domain (ECL2FtsX). Some FtsX suppressors are allele specific for changes in CCPcsB, and no FtsX suppressors were found for amino acid changes in the catalytic PcsB CHAP domain (CHAPPcsB). These results strongly support roles for both ECL1FtsX and ECL2FtsX in signal transduction to the coiled-coil domain of PcsB. Finally, we found that pcsBCC(Ts) mutants (Ts mutants carrying mutations in the region of pcsB corresponding to the coiled-coil domain) unexpectedly exhibit delayed stationary-phase autolysis at a permissive growth temperature. IMPORTANCE Little is known about how FtsX interacts with cognate PG hydrolases in any bacterium, besides that ECL1FtsX domains somehow interact with coiled-coil domains. This work used powerful genetic approaches to implicate a specific region of pneumococcal ECL1FtsX and the small ECL2FtsX in the interaction with CCPcsB. These findings identify amino acids important for in vivo signal transduction between FtsX and PcsB for the first time. This paper also supports the central hypothesis that signal transduction between pneumococcal FtsX and PcsB is linked to ATP hydrolysis by essential FtsE, which couples PG hydrolysis to cell division. The classical genetic approaches used here can be applied to dissect interactions of other integral membrane proteins involved in PG biosynthesis. Finally, delayed autolysis of the pcsBCC(Ts) mutants suggests that the FtsEX-PcsB PG hydrolase may generate a signal in the PG necessary for activation of the major LytA autolysin as pneumococcal cells enter stationary phase.
format	article
author	Lok-To Sham Katelyn R. Jensen Kevin E. Bruce Malcolm E. Winkler
author_facet	Lok-To Sham Katelyn R. Jensen Kevin E. Bruce Malcolm E. Winkler
author_sort	Lok-To Sham
title	Involvement of FtsE ATPase and FtsX Extracellular Loops 1 and 2 in FtsEX-PcsB Complex Function in Cell Division of <named-content content-type="genus-species">Streptococcus pneumoniae</named-content> D39
title_short	Involvement of FtsE ATPase and FtsX Extracellular Loops 1 and 2 in FtsEX-PcsB Complex Function in Cell Division of <named-content content-type="genus-species">Streptococcus pneumoniae</named-content> D39
title_full	Involvement of FtsE ATPase and FtsX Extracellular Loops 1 and 2 in FtsEX-PcsB Complex Function in Cell Division of <named-content content-type="genus-species">Streptococcus pneumoniae</named-content> D39
title_fullStr	Involvement of FtsE ATPase and FtsX Extracellular Loops 1 and 2 in FtsEX-PcsB Complex Function in Cell Division of <named-content content-type="genus-species">Streptococcus pneumoniae</named-content> D39
title_full_unstemmed	Involvement of FtsE ATPase and FtsX Extracellular Loops 1 and 2 in FtsEX-PcsB Complex Function in Cell Division of <named-content content-type="genus-species">Streptococcus pneumoniae</named-content> D39
title_sort	involvement of ftse atpase and ftsx extracellular loops 1 and 2 in ftsex-pcsb complex function in cell division of <named-content content-type="genus-species">streptococcus pneumoniae</named-content> d39
publisher	American Society for Microbiology
publishDate	2013
url	https://doaj.org/article/7a3b2381d75c40778e334566d4e79b94
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Involvement of FtsE ATPase and FtsX Extracellular Loops 1 and 2 in FtsEX-PcsB Complex Function in Cell Division of <named-content content-type="genus-species">Streptococcus pneumoniae</named-content> D39

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