Molecular and functional profiling of Gαi as an intracellular pH sensor
Abstract Heterotrimeric G proteins (Gα, Gβ and Gγ) act downstream of G-protein-coupled receptors (GPCRs) to mediate signaling pathways that regulate various physiological processes and human disease conditions. While human Gαi and its yeast homolog Gpa1 were previously postulated to function as intr...
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Nature Portfolio
2025-04-01
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| Series: | Nature Communications |
| Online Access: | https://doi.org/10.1038/s41467-025-58323-2 |
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| author | Ajit Prakash Zijian Li Venkat R. Chirasani Juhi A. Rasquinha Natalie Hewitt Garrett B. Hubbard Guowei Yin Aspen T. Hawkins Luca J. Montore Henrik G. Dohlman Sharon L. Campbell |
| author_facet | Ajit Prakash Zijian Li Venkat R. Chirasani Juhi A. Rasquinha Natalie Hewitt Garrett B. Hubbard Guowei Yin Aspen T. Hawkins Luca J. Montore Henrik G. Dohlman Sharon L. Campbell |
| author_sort | Ajit Prakash |
| collection | DOAJ |
| description | Abstract Heterotrimeric G proteins (Gα, Gβ and Gγ) act downstream of G-protein-coupled receptors (GPCRs) to mediate signaling pathways that regulate various physiological processes and human disease conditions. While human Gαi and its yeast homolog Gpa1 were previously postulated to function as intracellular pH sensors, the pH–sensing capabilities of Gαi and the underlying mechanism remain to be established. Our research shows that variations in pH significantly affect the structure and stability of Gαi-GDP. Specifically, at the lower end of the physiological pH range, the protein undergoes an order-to-disorder transition due to the loss of electrostatic interactions within the Gαi Switch regions, resulting in a reduction in agonist-mediated Gαi-Gβγ release. Further, we identified key residues within the Gαi Switch regions that form the pH–sensing network. Mutation of these residues in Gαi gives rise to ‘low pH mimetics’ that abolish pH-dependent thermostability changes and reduce Gαi-Gβγ release. Overall, our findings suggest that pH-sensitive structural changes in Gαi impact the agonist-mediated dissociation of Gβγ, which is essential for proper signaling. |
| format | Article |
| id | doaj-art-145730295e2c47619a5154a73bfaaa24 |
| institution | DOAJ |
| issn | 2041-1723 |
| language | English |
| publishDate | 2025-04-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | Nature Communications |
| spelling | doaj-art-145730295e2c47619a5154a73bfaaa242025-08-20T03:10:13ZengNature PortfolioNature Communications2041-17232025-04-0116111510.1038/s41467-025-58323-2Molecular and functional profiling of Gαi as an intracellular pH sensorAjit Prakash0Zijian Li1Venkat R. Chirasani2Juhi A. Rasquinha3Natalie Hewitt4Garrett B. Hubbard5Guowei Yin6Aspen T. Hawkins7Luca J. Montore8Henrik G. Dohlman9Sharon L. Campbell10Department of Biochemistry & Biophysics, University of North Carolina at Chapel HillDepartment of Biochemistry & Biophysics, University of North Carolina at Chapel HillDepartment of Biochemistry & Biophysics, University of North Carolina at Chapel HillDepartment of Biochemistry & Biophysics, University of North Carolina at Chapel HillDepartment of Pharmacology, University of North Carolina at Chapel HillDepartment of Biochemistry & Biophysics, University of North Carolina at Chapel HillThe Seventh Affiliated Hospital of Sun Yat-sen UniversityDepartment of Biochemistry & Biophysics, University of North Carolina at Chapel HillDepartment of Biochemistry & Biophysics, University of North Carolina at Chapel HillDepartment of Pharmacology, University of North Carolina at Chapel HillDepartment of Biochemistry & Biophysics, University of North Carolina at Chapel HillAbstract Heterotrimeric G proteins (Gα, Gβ and Gγ) act downstream of G-protein-coupled receptors (GPCRs) to mediate signaling pathways that regulate various physiological processes and human disease conditions. While human Gαi and its yeast homolog Gpa1 were previously postulated to function as intracellular pH sensors, the pH–sensing capabilities of Gαi and the underlying mechanism remain to be established. Our research shows that variations in pH significantly affect the structure and stability of Gαi-GDP. Specifically, at the lower end of the physiological pH range, the protein undergoes an order-to-disorder transition due to the loss of electrostatic interactions within the Gαi Switch regions, resulting in a reduction in agonist-mediated Gαi-Gβγ release. Further, we identified key residues within the Gαi Switch regions that form the pH–sensing network. Mutation of these residues in Gαi gives rise to ‘low pH mimetics’ that abolish pH-dependent thermostability changes and reduce Gαi-Gβγ release. Overall, our findings suggest that pH-sensitive structural changes in Gαi impact the agonist-mediated dissociation of Gβγ, which is essential for proper signaling.https://doi.org/10.1038/s41467-025-58323-2 |
| spellingShingle | Ajit Prakash Zijian Li Venkat R. Chirasani Juhi A. Rasquinha Natalie Hewitt Garrett B. Hubbard Guowei Yin Aspen T. Hawkins Luca J. Montore Henrik G. Dohlman Sharon L. Campbell Molecular and functional profiling of Gαi as an intracellular pH sensor Nature Communications |
| title | Molecular and functional profiling of Gαi as an intracellular pH sensor |
| title_full | Molecular and functional profiling of Gαi as an intracellular pH sensor |
| title_fullStr | Molecular and functional profiling of Gαi as an intracellular pH sensor |
| title_full_unstemmed | Molecular and functional profiling of Gαi as an intracellular pH sensor |
| title_short | Molecular and functional profiling of Gαi as an intracellular pH sensor |
| title_sort | molecular and functional profiling of gαi as an intracellular ph sensor |
| url | https://doi.org/10.1038/s41467-025-58323-2 |
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