Enhanced uptake of potassium or glycine betaine or export of cyclic-di-AMP restores osmoresistance in a high cyclic-di-AMP Lactococcus lactis mutant

Huong Thi Pham, Nguyen Thi Hanh Nhiep, Thu Ngoc Minh Vu, Tu Anh Ngoc Huynh, Yan Zhu, Anh Le Diep Huynh, Alolika Chakrabortti, Esteban Marcellin, Raquel Lo, Christopher B. Howard, Nidhi Bansal, Joshua J. Woodward, Zhao Xun Liang, Mark S. Turner

Research output: Contribution to journalArticleResearchpeer-review

Abstract

The broadly conserved bacterial signalling molecule cyclic-di-adenosine monophosphate (c-di-AMP) controls osmoresistance via its regulation of potassium (K + ) and compatible solute uptake. High levels of c-di-AMP resulting from inactivation of c-di-AMP phosphodiesterase activity leads to poor growth of bacteria under high osmotic conditions. To better understand how bacteria can adjust in response to excessive c-di-AMP levels and to identify signals that feed into the c-di-AMP network, we characterised genes identified in a screen for osmoresistant suppressor mutants of the high c-di-AMP Lactococcus ΔgdpP strain. Mutations were identified which increased the uptake of osmoprotectants, including gain-of-function mutations in a Kup family K + importer (KupB) and inactivation of the glycine betaine transporter transcriptional repressor BusR. The KupB mutations increased the intracellular K + level while BusR inactivation increased the glycine betaine level. In addition, BusR was found to directly bind c-di-AMP and repress expression of the glycine betaine transporter in response to elevated c-di-AMP. Interestingly, overactive KupB activity or loss of BusR triggered c-di-AMP accumulation, suggesting turgor pressure changes act as a signal for this second messenger. In another group of suppressors, overexpression of an operon encoding an EmrB family multidrug resistance protein allowed cells to lower their intracellular level of c-di-AMP through active export. Lastly evidence is provided that c-di-AMP levels in several bacteria are rapidly responsive to environmental osmolarity changes. Taken together, this work provides evidence for a model in which high c-di-AMP containing cells are dehydrated due to lower K + and compatible solute levels and that this osmoregulation system is able to sense and respond to cellular water stress.

Original languageEnglish
Article numbere1007574
Number of pages23
JournalPLoS Genetics
Volume14
Issue number8
DOIs
Publication statusPublished - 3 Aug 2018

Keywords

  • glycine
  • osmotic pressure
  • suppressor genes
  • operons
  • listeria monocytogenes
  • deletion mutation
  • hyperexpression techniques
  • gene pool

Cite this

Pham, Huong Thi ; Nhiep, Nguyen Thi Hanh ; Vu, Thu Ngoc Minh ; Huynh, Tu Anh Ngoc ; Zhu, Yan ; Huynh, Anh Le Diep ; Chakrabortti, Alolika ; Marcellin, Esteban ; Lo, Raquel ; Howard, Christopher B. ; Bansal, Nidhi ; Woodward, Joshua J. ; Liang, Zhao Xun ; Turner, Mark S. / Enhanced uptake of potassium or glycine betaine or export of cyclic-di-AMP restores osmoresistance in a high cyclic-di-AMP Lactococcus lactis mutant. In: PLoS Genetics. 2018 ; Vol. 14, No. 8.
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title = "Enhanced uptake of potassium or glycine betaine or export of cyclic-di-AMP restores osmoresistance in a high cyclic-di-AMP Lactococcus lactis mutant",
abstract = "The broadly conserved bacterial signalling molecule cyclic-di-adenosine monophosphate (c-di-AMP) controls osmoresistance via its regulation of potassium (K + ) and compatible solute uptake. High levels of c-di-AMP resulting from inactivation of c-di-AMP phosphodiesterase activity leads to poor growth of bacteria under high osmotic conditions. To better understand how bacteria can adjust in response to excessive c-di-AMP levels and to identify signals that feed into the c-di-AMP network, we characterised genes identified in a screen for osmoresistant suppressor mutants of the high c-di-AMP Lactococcus ΔgdpP strain. Mutations were identified which increased the uptake of osmoprotectants, including gain-of-function mutations in a Kup family K + importer (KupB) and inactivation of the glycine betaine transporter transcriptional repressor BusR. The KupB mutations increased the intracellular K + level while BusR inactivation increased the glycine betaine level. In addition, BusR was found to directly bind c-di-AMP and repress expression of the glycine betaine transporter in response to elevated c-di-AMP. Interestingly, overactive KupB activity or loss of BusR triggered c-di-AMP accumulation, suggesting turgor pressure changes act as a signal for this second messenger. In another group of suppressors, overexpression of an operon encoding an EmrB family multidrug resistance protein allowed cells to lower their intracellular level of c-di-AMP through active export. Lastly evidence is provided that c-di-AMP levels in several bacteria are rapidly responsive to environmental osmolarity changes. Taken together, this work provides evidence for a model in which high c-di-AMP containing cells are dehydrated due to lower K + and compatible solute levels and that this osmoregulation system is able to sense and respond to cellular water stress.",
keywords = "glycine, osmotic pressure, suppressor genes, operons, listeria monocytogenes, deletion mutation, hyperexpression techniques, gene pool",
author = "Pham, {Huong Thi} and Nhiep, {Nguyen Thi Hanh} and Vu, {Thu Ngoc Minh} and Huynh, {Tu Anh Ngoc} and Yan Zhu and Huynh, {Anh Le Diep} and Alolika Chakrabortti and Esteban Marcellin and Raquel Lo and Howard, {Christopher B.} and Nidhi Bansal and Woodward, {Joshua J.} and Liang, {Zhao Xun} and Turner, {Mark S.}",
year = "2018",
month = "8",
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doi = "10.1371/journal.pgen.1007574",
language = "English",
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Pham, HT, Nhiep, NTH, Vu, TNM, Huynh, TAN, Zhu, Y, Huynh, ALD, Chakrabortti, A, Marcellin, E, Lo, R, Howard, CB, Bansal, N, Woodward, JJ, Liang, ZX & Turner, MS 2018, 'Enhanced uptake of potassium or glycine betaine or export of cyclic-di-AMP restores osmoresistance in a high cyclic-di-AMP Lactococcus lactis mutant' PLoS Genetics, vol. 14, no. 8, e1007574. https://doi.org/10.1371/journal.pgen.1007574

Enhanced uptake of potassium or glycine betaine or export of cyclic-di-AMP restores osmoresistance in a high cyclic-di-AMP Lactococcus lactis mutant. / Pham, Huong Thi; Nhiep, Nguyen Thi Hanh; Vu, Thu Ngoc Minh; Huynh, Tu Anh Ngoc; Zhu, Yan; Huynh, Anh Le Diep; Chakrabortti, Alolika; Marcellin, Esteban; Lo, Raquel; Howard, Christopher B.; Bansal, Nidhi; Woodward, Joshua J.; Liang, Zhao Xun; Turner, Mark S.

In: PLoS Genetics, Vol. 14, No. 8, e1007574, 03.08.2018.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Enhanced uptake of potassium or glycine betaine or export of cyclic-di-AMP restores osmoresistance in a high cyclic-di-AMP Lactococcus lactis mutant

AU - Pham, Huong Thi

AU - Nhiep, Nguyen Thi Hanh

AU - Vu, Thu Ngoc Minh

AU - Huynh, Tu Anh Ngoc

AU - Zhu, Yan

AU - Huynh, Anh Le Diep

AU - Chakrabortti, Alolika

AU - Marcellin, Esteban

AU - Lo, Raquel

AU - Howard, Christopher B.

AU - Bansal, Nidhi

AU - Woodward, Joshua J.

AU - Liang, Zhao Xun

AU - Turner, Mark S.

PY - 2018/8/3

Y1 - 2018/8/3

N2 - The broadly conserved bacterial signalling molecule cyclic-di-adenosine monophosphate (c-di-AMP) controls osmoresistance via its regulation of potassium (K + ) and compatible solute uptake. High levels of c-di-AMP resulting from inactivation of c-di-AMP phosphodiesterase activity leads to poor growth of bacteria under high osmotic conditions. To better understand how bacteria can adjust in response to excessive c-di-AMP levels and to identify signals that feed into the c-di-AMP network, we characterised genes identified in a screen for osmoresistant suppressor mutants of the high c-di-AMP Lactococcus ΔgdpP strain. Mutations were identified which increased the uptake of osmoprotectants, including gain-of-function mutations in a Kup family K + importer (KupB) and inactivation of the glycine betaine transporter transcriptional repressor BusR. The KupB mutations increased the intracellular K + level while BusR inactivation increased the glycine betaine level. In addition, BusR was found to directly bind c-di-AMP and repress expression of the glycine betaine transporter in response to elevated c-di-AMP. Interestingly, overactive KupB activity or loss of BusR triggered c-di-AMP accumulation, suggesting turgor pressure changes act as a signal for this second messenger. In another group of suppressors, overexpression of an operon encoding an EmrB family multidrug resistance protein allowed cells to lower their intracellular level of c-di-AMP through active export. Lastly evidence is provided that c-di-AMP levels in several bacteria are rapidly responsive to environmental osmolarity changes. Taken together, this work provides evidence for a model in which high c-di-AMP containing cells are dehydrated due to lower K + and compatible solute levels and that this osmoregulation system is able to sense and respond to cellular water stress.

AB - The broadly conserved bacterial signalling molecule cyclic-di-adenosine monophosphate (c-di-AMP) controls osmoresistance via its regulation of potassium (K + ) and compatible solute uptake. High levels of c-di-AMP resulting from inactivation of c-di-AMP phosphodiesterase activity leads to poor growth of bacteria under high osmotic conditions. To better understand how bacteria can adjust in response to excessive c-di-AMP levels and to identify signals that feed into the c-di-AMP network, we characterised genes identified in a screen for osmoresistant suppressor mutants of the high c-di-AMP Lactococcus ΔgdpP strain. Mutations were identified which increased the uptake of osmoprotectants, including gain-of-function mutations in a Kup family K + importer (KupB) and inactivation of the glycine betaine transporter transcriptional repressor BusR. The KupB mutations increased the intracellular K + level while BusR inactivation increased the glycine betaine level. In addition, BusR was found to directly bind c-di-AMP and repress expression of the glycine betaine transporter in response to elevated c-di-AMP. Interestingly, overactive KupB activity or loss of BusR triggered c-di-AMP accumulation, suggesting turgor pressure changes act as a signal for this second messenger. In another group of suppressors, overexpression of an operon encoding an EmrB family multidrug resistance protein allowed cells to lower their intracellular level of c-di-AMP through active export. Lastly evidence is provided that c-di-AMP levels in several bacteria are rapidly responsive to environmental osmolarity changes. Taken together, this work provides evidence for a model in which high c-di-AMP containing cells are dehydrated due to lower K + and compatible solute levels and that this osmoregulation system is able to sense and respond to cellular water stress.

KW - glycine

KW - osmotic pressure

KW - suppressor genes

KW - operons

KW - listeria monocytogenes

KW - deletion mutation

KW - hyperexpression techniques

KW - gene pool

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U2 - 10.1371/journal.pgen.1007574

DO - 10.1371/journal.pgen.1007574

M3 - Article

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JO - PLoS Genetics

JF - PLoS Genetics

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