Cyclic di-AMP traps proton-coupled K+ transporters of the KUP family in an inward-occluded conformation
Abstract Cyclic di-AMP is the only known essential second messenger in bacteria and archaea, regulating different proteins indispensable for numerous physiological processes. In particular, it controls various potassium and osmolyte transporters involved in osmoregulation. In Bacillus subtilis, the...
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| Format: | Article |
| Language: | English |
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Nature Portfolio
2023-06-01
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| Series: | Nature Communications |
| Online Access: | https://doi.org/10.1038/s41467-023-38944-1 |
| _version_ | 1797795611281457152 |
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| author | Michael F. Fuss Jan-Philip Wieferig Robin A. Corey Yvonne Hellmich Igor Tascón Joana S. Sousa Phillip J. Stansfeld Janet Vonck Inga Hänelt |
| author_facet | Michael F. Fuss Jan-Philip Wieferig Robin A. Corey Yvonne Hellmich Igor Tascón Joana S. Sousa Phillip J. Stansfeld Janet Vonck Inga Hänelt |
| author_sort | Michael F. Fuss |
| collection | DOAJ |
| description | Abstract Cyclic di-AMP is the only known essential second messenger in bacteria and archaea, regulating different proteins indispensable for numerous physiological processes. In particular, it controls various potassium and osmolyte transporters involved in osmoregulation. In Bacillus subtilis, the K+/H+ symporter KimA of the KUP family is inactivated by c-di-AMP. KimA sustains survival at potassium limitation at low external pH by mediating potassium ion uptake. However, at elevated intracellular K+ concentrations, further K+ accumulation would be toxic. In this study, we reveal the molecular basis of how c-di-AMP binding inhibits KimA. We report cryo-EM structures of KimA with bound c-di-AMP in detergent solution and reconstituted in amphipols. By combining structural data with functional assays and molecular dynamics simulations we reveal how c-di-AMP modulates transport. We show that an intracellular loop in the transmembrane domain interacts with c-di-AMP bound to the adjacent cytosolic domain. This reduces the mobility of transmembrane helices at the cytosolic side of the K+ binding site and therefore traps KimA in an inward-occluded conformation. |
| first_indexed | 2024-03-13T03:20:35Z |
| format | Article |
| id | doaj.art-d7e604588b594a688deb0ddfbae8a895 |
| institution | Directory Open Access Journal |
| issn | 2041-1723 |
| language | English |
| last_indexed | 2024-03-13T03:20:35Z |
| publishDate | 2023-06-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | Nature Communications |
| spelling | doaj.art-d7e604588b594a688deb0ddfbae8a8952023-06-25T11:21:36ZengNature PortfolioNature Communications2041-17232023-06-0114111210.1038/s41467-023-38944-1Cyclic di-AMP traps proton-coupled K+ transporters of the KUP family in an inward-occluded conformationMichael F. Fuss0Jan-Philip Wieferig1Robin A. Corey2Yvonne Hellmich3Igor Tascón4Joana S. Sousa5Phillip J. Stansfeld6Janet Vonck7Inga Hänelt8Institute of Biochemistry, Goethe University FrankfurtDepartment of Structural Biology, Max Planck Institute of BiophysicsDepartment of Biochemistry, University of OxfordInstitute of Biochemistry, Goethe University FrankfurtInstitute of Biochemistry, Goethe University FrankfurtDepartment of Structural Biology, Max Planck Institute of BiophysicsSchool of Life Sciences & Department of Chemistry, University of WarwickDepartment of Structural Biology, Max Planck Institute of BiophysicsInstitute of Biochemistry, Goethe University FrankfurtAbstract Cyclic di-AMP is the only known essential second messenger in bacteria and archaea, regulating different proteins indispensable for numerous physiological processes. In particular, it controls various potassium and osmolyte transporters involved in osmoregulation. In Bacillus subtilis, the K+/H+ symporter KimA of the KUP family is inactivated by c-di-AMP. KimA sustains survival at potassium limitation at low external pH by mediating potassium ion uptake. However, at elevated intracellular K+ concentrations, further K+ accumulation would be toxic. In this study, we reveal the molecular basis of how c-di-AMP binding inhibits KimA. We report cryo-EM structures of KimA with bound c-di-AMP in detergent solution and reconstituted in amphipols. By combining structural data with functional assays and molecular dynamics simulations we reveal how c-di-AMP modulates transport. We show that an intracellular loop in the transmembrane domain interacts with c-di-AMP bound to the adjacent cytosolic domain. This reduces the mobility of transmembrane helices at the cytosolic side of the K+ binding site and therefore traps KimA in an inward-occluded conformation.https://doi.org/10.1038/s41467-023-38944-1 |
| spellingShingle | Michael F. Fuss Jan-Philip Wieferig Robin A. Corey Yvonne Hellmich Igor Tascón Joana S. Sousa Phillip J. Stansfeld Janet Vonck Inga Hänelt Cyclic di-AMP traps proton-coupled K+ transporters of the KUP family in an inward-occluded conformation Nature Communications |
| title | Cyclic di-AMP traps proton-coupled K+ transporters of the KUP family in an inward-occluded conformation |
| title_full | Cyclic di-AMP traps proton-coupled K+ transporters of the KUP family in an inward-occluded conformation |
| title_fullStr | Cyclic di-AMP traps proton-coupled K+ transporters of the KUP family in an inward-occluded conformation |
| title_full_unstemmed | Cyclic di-AMP traps proton-coupled K+ transporters of the KUP family in an inward-occluded conformation |
| title_short | Cyclic di-AMP traps proton-coupled K+ transporters of the KUP family in an inward-occluded conformation |
| title_sort | cyclic di amp traps proton coupled k transporters of the kup family in an inward occluded conformation |
| url | https://doi.org/10.1038/s41467-023-38944-1 |
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