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 language | English |
|---|---|
| Article number | e1007574 |
| Number of pages | 23 |
| Journal | PLoS Genetics |
| Volume | 14 |
| Issue number | 8 |
| DOIs | |
| Publication status | Published - 3 Aug 2018 |
Keywords
- glycine
- osmotic pressure
- suppressor genes
- operons
- listeria monocytogenes
- deletion mutation
- hyperexpression techniques
- gene pool
Cite this
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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 journal › Article › Research › peer-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
UR - http://www.scopus.com/inward/record.url?scp=85053073850&partnerID=8YFLogxK
U2 - 10.1371/journal.pgen.1007574
DO - 10.1371/journal.pgen.1007574
M3 - Article
VL - 14
JO - PLoS Genetics
JF - PLoS Genetics
SN - 1553-7390
IS - 8
M1 - e1007574
ER -