Regulation of the Sae Two-Component System by Branched-Chain Fatty Acids in Staphylococcus aureus
ABSTRACT Staphylococcus aureus is a ubiquitous Gram-positive bacterium and an opportunistic human pathogen. S. aureus pathogenesis relies on a complex network of regulatory factors that adjust gene expression. Two important factors in this network are CodY, a repressor protein responsive to nutrient...
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| Format: | Article |
| Language: | English |
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American Society for Microbiology
2022-10-01
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| Series: | mBio |
| Subjects: | |
| Online Access: | https://journals.asm.org/doi/10.1128/mbio.01472-22 |
| _version_ | 1811329357424099328 |
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| author | Augustus Pendleton Won-Sik Yeo Shahad Alqahtani Dennis A. DiMaggio Carl J. Stone Zhaotao Li Vineet K. Singh Christopher P. Montgomery Taeok Bae Shaun R. Brinsmade |
| author_facet | Augustus Pendleton Won-Sik Yeo Shahad Alqahtani Dennis A. DiMaggio Carl J. Stone Zhaotao Li Vineet K. Singh Christopher P. Montgomery Taeok Bae Shaun R. Brinsmade |
| author_sort | Augustus Pendleton |
| collection | DOAJ |
| description | ABSTRACT Staphylococcus aureus is a ubiquitous Gram-positive bacterium and an opportunistic human pathogen. S. aureus pathogenesis relies on a complex network of regulatory factors that adjust gene expression. Two important factors in this network are CodY, a repressor protein responsive to nutrient availability, and the SaeRS two-component system (TCS), which responds to neutrophil-produced factors. Our previous work revealed that CodY regulates the secretion of many toxins indirectly via Sae through an unknown mechanism. We report that disruption of codY results in increased levels of phosphorylated SaeR (SaeR~P) and that codY mutant cell membranes contain a higher percentage of branched-chain fatty acids (BCFAs) than do wild-type membranes, prompting us to hypothesize that changes to membrane composition modulate the activity of the SaeS sensor kinase. Disrupting the lpdA gene encoding dihydrolipoyl dehydrogenase, which is critical for BCFA synthesis, significantly reduced the abundance of SaeR, phosphorylated SaeR, and BCFAs in the membrane, resulting in reduced toxin production and attenuated virulence. Lower SaeR levels could be explained in part by reduced stability. Sae activity in the lpdA mutant could be complemented genetically and chemically with exogenous short- or full-length BCFAs. Intriguingly, lack of lpdA also alters the activity of other TCSs, suggesting a specific BCFA requirement managing the basal activity of multiple TCSs. These results reveal a novel method of posttranscriptional virulence regulation via BCFA synthesis, potentially linking CodY activity to multiple virulence regulators in S. aureus. IMPORTANCE Two-component systems (TCSs) are an essential way that bacteria sense and respond to their environment. These systems are usually composed of a membrane-bound histidine kinase that phosphorylates a cytoplasmic response regulator. Because most of the histidine kinases are embedded in the membrane, lipids can allosterically regulate the activity of these sensors. In this study, we reveal that branched-chain fatty acids (BCFAs) are required for the activation of multiple TCSs in Staphylococcus aureus. Using both genetic and biochemical data, we show that the activity of the virulence activator SaeS and the phosphorylation of its response regulator SaeR are reduced in a branched-chain keto-acid dehydrogenase complex mutant and that defects in BCFA synthesis have far-reaching consequences for exotoxin secretion and virulence. Finally, we show that mutation of the global nutritional regulator CodY alters BCFA content in the membrane, revealing a potential mechanism of posttranscriptional regulation of the Sae system by CodY. |
| first_indexed | 2024-04-13T15:42:30Z |
| format | Article |
| id | doaj.art-ca8119e7cbe4480488831df51158cfed |
| institution | Directory Open Access Journal |
| issn | 2150-7511 |
| language | English |
| last_indexed | 2024-04-13T15:42:30Z |
| publishDate | 2022-10-01 |
| publisher | American Society for Microbiology |
| record_format | Article |
| series | mBio |
| spelling | doaj.art-ca8119e7cbe4480488831df51158cfed2022-12-22T02:41:07ZengAmerican Society for MicrobiologymBio2150-75112022-10-0113510.1128/mbio.01472-22Regulation of the Sae Two-Component System by Branched-Chain Fatty Acids in Staphylococcus aureusAugustus Pendleton0Won-Sik Yeo1Shahad Alqahtani2Dennis A. DiMaggio3Carl J. Stone4Zhaotao Li5Vineet K. Singh6Christopher P. Montgomery7Taeok Bae8Shaun R. Brinsmade9Department of Biology, Georgetown University, Washington, DC, USADepartment of Biology, Georgetown University, Washington, DC, USADepartment of Biology, Georgetown University, Washington, DC, USADepartment of Biology, Georgetown University, Washington, DC, USADepartment of Biology, Georgetown University, Washington, DC, USACenter for Microbial Pathogenesis, Abigail Wexner Institute at Nationwide Children’s Hospital, Columbus, Ohio, USADepartment of Microbiology and Immunology, A.T. Still University of Health Sciences, Kirksville, Missouri, USACenter for Microbial Pathogenesis, Abigail Wexner Institute at Nationwide Children’s Hospital, Columbus, Ohio, USADepartment of Microbiology and Immunology, Indiana University School of Medicine-Northwest, Gary, Indiana, USADepartment of Biology, Georgetown University, Washington, DC, USAABSTRACT Staphylococcus aureus is a ubiquitous Gram-positive bacterium and an opportunistic human pathogen. S. aureus pathogenesis relies on a complex network of regulatory factors that adjust gene expression. Two important factors in this network are CodY, a repressor protein responsive to nutrient availability, and the SaeRS two-component system (TCS), which responds to neutrophil-produced factors. Our previous work revealed that CodY regulates the secretion of many toxins indirectly via Sae through an unknown mechanism. We report that disruption of codY results in increased levels of phosphorylated SaeR (SaeR~P) and that codY mutant cell membranes contain a higher percentage of branched-chain fatty acids (BCFAs) than do wild-type membranes, prompting us to hypothesize that changes to membrane composition modulate the activity of the SaeS sensor kinase. Disrupting the lpdA gene encoding dihydrolipoyl dehydrogenase, which is critical for BCFA synthesis, significantly reduced the abundance of SaeR, phosphorylated SaeR, and BCFAs in the membrane, resulting in reduced toxin production and attenuated virulence. Lower SaeR levels could be explained in part by reduced stability. Sae activity in the lpdA mutant could be complemented genetically and chemically with exogenous short- or full-length BCFAs. Intriguingly, lack of lpdA also alters the activity of other TCSs, suggesting a specific BCFA requirement managing the basal activity of multiple TCSs. These results reveal a novel method of posttranscriptional virulence regulation via BCFA synthesis, potentially linking CodY activity to multiple virulence regulators in S. aureus. IMPORTANCE Two-component systems (TCSs) are an essential way that bacteria sense and respond to their environment. These systems are usually composed of a membrane-bound histidine kinase that phosphorylates a cytoplasmic response regulator. Because most of the histidine kinases are embedded in the membrane, lipids can allosterically regulate the activity of these sensors. In this study, we reveal that branched-chain fatty acids (BCFAs) are required for the activation of multiple TCSs in Staphylococcus aureus. Using both genetic and biochemical data, we show that the activity of the virulence activator SaeS and the phosphorylation of its response regulator SaeR are reduced in a branched-chain keto-acid dehydrogenase complex mutant and that defects in BCFA synthesis have far-reaching consequences for exotoxin secretion and virulence. Finally, we show that mutation of the global nutritional regulator CodY alters BCFA content in the membrane, revealing a potential mechanism of posttranscriptional regulation of the Sae system by CodY.https://journals.asm.org/doi/10.1128/mbio.01472-22MRSAStaphylococcus aureusSaeRSvirulencemembranebranched-chain fatty acids |
| spellingShingle | Augustus Pendleton Won-Sik Yeo Shahad Alqahtani Dennis A. DiMaggio Carl J. Stone Zhaotao Li Vineet K. Singh Christopher P. Montgomery Taeok Bae Shaun R. Brinsmade Regulation of the Sae Two-Component System by Branched-Chain Fatty Acids in Staphylococcus aureus mBio MRSA Staphylococcus aureus SaeRS virulence membrane branched-chain fatty acids |
| title | Regulation of the Sae Two-Component System by Branched-Chain Fatty Acids in Staphylococcus aureus |
| title_full | Regulation of the Sae Two-Component System by Branched-Chain Fatty Acids in Staphylococcus aureus |
| title_fullStr | Regulation of the Sae Two-Component System by Branched-Chain Fatty Acids in Staphylococcus aureus |
| title_full_unstemmed | Regulation of the Sae Two-Component System by Branched-Chain Fatty Acids in Staphylococcus aureus |
| title_short | Regulation of the Sae Two-Component System by Branched-Chain Fatty Acids in Staphylococcus aureus |
| title_sort | regulation of the sae two component system by branched chain fatty acids in staphylococcus aureus |
| topic | MRSA Staphylococcus aureus SaeRS virulence membrane branched-chain fatty acids |
| url | https://journals.asm.org/doi/10.1128/mbio.01472-22 |
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