GraS signaling in Staphylococcus aureus is regulated by a single D35 residue in the extracellular loop
ABSTRACT Bacterial two-component systems are crucial features of bacterial pathogens such as methicillin-resistant Staphylococcus aureus to overcome environmental and antimicrobial stresses by activating regulons to interfere with the bactericidal mechanisms. GraRS is a unique subset of two-componen...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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American Society for Microbiology
2023-10-01
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| Series: | Microbiology Spectrum |
| Subjects: | |
| Online Access: | https://journals.asm.org/doi/10.1128/spectrum.01982-23 |
| _version_ | 1797658180908482560 |
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| author | Junho Cho Adhar C. Manna Helah S. Snelling Ambrose L. Cheung |
| author_facet | Junho Cho Adhar C. Manna Helah S. Snelling Ambrose L. Cheung |
| author_sort | Junho Cho |
| collection | DOAJ |
| description | ABSTRACT Bacterial two-component systems are crucial features of bacterial pathogens such as methicillin-resistant Staphylococcus aureus to overcome environmental and antimicrobial stresses by activating regulons to interfere with the bactericidal mechanisms. GraRS is a unique subset of two-component systems belonging to the intramembrane-sensing histidine kinase family (IM-HK) and is responsible for resistance to cationic host defense peptides. However, the precise manner by which the short 9-residue extracellular loop of the membrane sensor GraS detects the antimicrobial peptides and transduces the signal is not comprehensively understood. Here, we show that a single point mutation (D35A) in the extracellular loop of GraS blocked activation of GraRS, but this effect was also abrogated with graS mutations in the N-terminal transmembrane segments without any accompanying effect on GraS protein expression. Additionally, mutations in H120 and T172 in the dimerization/histidine phosphotransfer (DHp) domain of GraS increased activation without any accompanying enhancement in dimerization, likely due to disruption of the H120-T172 interaction that restricts rotational movements of the DHp helices since swapping H120 and T172 did not alter GraS activation. Notably, the enhancing effects of H120 and T172 mutations were abolished with a D35 mutation, highlighting the pivotal role of D35 in the 9-residue extracellular loop of GraS in GraR phosphorylation. In summary, our study delivers the significance of the D35 in the extracellular loop of GraS and ensuing changes in the N-terminal transmembrane helices as a model to illustrate signaling in the IM-HK subset of two-component regulatory systems. IMPORTANCE Methicillin-resistant Staphylococcus aureus (MRSA) is a human pathogen capable of infecting skin, blood, internal organs, and artificial medical devices. Generally, personal hygiene and a robust immune system can limit the spread of this pathogen; however, MRSA possesses an assortment of phenotypic tools to survive the hostile host environment including host defense peptides. More specifically, S. aureus utilizes two-component systems to sense noxious environmental cues to respond to harmful environmental elements. Our study focused on a two-component system called GraRS that S. aureus deploys against host defense peptides. We showed that one single residue in the extracellular loop of GraS and the adjacent membrane segment controlled the activation of GraRS, indicating the importance of a well-tuned-charged residue in the extracellular loop of GraS for sensing activity. |
| first_indexed | 2024-03-11T17:55:23Z |
| format | Article |
| id | doaj.art-bc44db0c2e65456ebe70a8fdfcf4d581 |
| institution | Directory Open Access Journal |
| issn | 2165-0497 |
| language | English |
| last_indexed | 2024-03-11T17:55:23Z |
| publishDate | 2023-10-01 |
| publisher | American Society for Microbiology |
| record_format | Article |
| series | Microbiology Spectrum |
| spelling | doaj.art-bc44db0c2e65456ebe70a8fdfcf4d5812023-10-17T13:04:36ZengAmerican Society for MicrobiologyMicrobiology Spectrum2165-04972023-10-0111510.1128/spectrum.01982-23GraS signaling in Staphylococcus aureus is regulated by a single D35 residue in the extracellular loopJunho Cho0Adhar C. Manna1Helah S. Snelling2Ambrose L. Cheung3Department of Microbiology and Immunology, Geisel School of Medicine, Dartmouth College , Hanover, New Hampshire, USADepartment of Microbiology and Immunology, Geisel School of Medicine, Dartmouth College , Hanover, New Hampshire, USADepartment of Microbiology and Immunology, Geisel School of Medicine, Dartmouth College , Hanover, New Hampshire, USADepartment of Microbiology and Immunology, Geisel School of Medicine, Dartmouth College , Hanover, New Hampshire, USAABSTRACT Bacterial two-component systems are crucial features of bacterial pathogens such as methicillin-resistant Staphylococcus aureus to overcome environmental and antimicrobial stresses by activating regulons to interfere with the bactericidal mechanisms. GraRS is a unique subset of two-component systems belonging to the intramembrane-sensing histidine kinase family (IM-HK) and is responsible for resistance to cationic host defense peptides. However, the precise manner by which the short 9-residue extracellular loop of the membrane sensor GraS detects the antimicrobial peptides and transduces the signal is not comprehensively understood. Here, we show that a single point mutation (D35A) in the extracellular loop of GraS blocked activation of GraRS, but this effect was also abrogated with graS mutations in the N-terminal transmembrane segments without any accompanying effect on GraS protein expression. Additionally, mutations in H120 and T172 in the dimerization/histidine phosphotransfer (DHp) domain of GraS increased activation without any accompanying enhancement in dimerization, likely due to disruption of the H120-T172 interaction that restricts rotational movements of the DHp helices since swapping H120 and T172 did not alter GraS activation. Notably, the enhancing effects of H120 and T172 mutations were abolished with a D35 mutation, highlighting the pivotal role of D35 in the 9-residue extracellular loop of GraS in GraR phosphorylation. In summary, our study delivers the significance of the D35 in the extracellular loop of GraS and ensuing changes in the N-terminal transmembrane helices as a model to illustrate signaling in the IM-HK subset of two-component regulatory systems. IMPORTANCE Methicillin-resistant Staphylococcus aureus (MRSA) is a human pathogen capable of infecting skin, blood, internal organs, and artificial medical devices. Generally, personal hygiene and a robust immune system can limit the spread of this pathogen; however, MRSA possesses an assortment of phenotypic tools to survive the hostile host environment including host defense peptides. More specifically, S. aureus utilizes two-component systems to sense noxious environmental cues to respond to harmful environmental elements. Our study focused on a two-component system called GraRS that S. aureus deploys against host defense peptides. We showed that one single residue in the extracellular loop of GraS and the adjacent membrane segment controlled the activation of GraRS, indicating the importance of a well-tuned-charged residue in the extracellular loop of GraS for sensing activity.https://journals.asm.org/doi/10.1128/spectrum.01982-23MRSAtwo-component regulatory systemsantimicrobial peptidesGraRS TCS |
| spellingShingle | Junho Cho Adhar C. Manna Helah S. Snelling Ambrose L. Cheung GraS signaling in Staphylococcus aureus is regulated by a single D35 residue in the extracellular loop Microbiology Spectrum MRSA two-component regulatory systems antimicrobial peptides GraRS TCS |
| title | GraS signaling in Staphylococcus aureus is regulated by a single D35 residue in the extracellular loop |
| title_full | GraS signaling in Staphylococcus aureus is regulated by a single D35 residue in the extracellular loop |
| title_fullStr | GraS signaling in Staphylococcus aureus is regulated by a single D35 residue in the extracellular loop |
| title_full_unstemmed | GraS signaling in Staphylococcus aureus is regulated by a single D35 residue in the extracellular loop |
| title_short | GraS signaling in Staphylococcus aureus is regulated by a single D35 residue in the extracellular loop |
| title_sort | gras signaling in staphylococcus aureus is regulated by a single d35 residue in the extracellular loop |
| topic | MRSA two-component regulatory systems antimicrobial peptides GraRS TCS |
| url | https://journals.asm.org/doi/10.1128/spectrum.01982-23 |
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