The intracellular domain of homomeric glycine receptors modulates agonist efficacy
| العنوان: | The intracellular domain of homomeric glycine receptors modulates agonist efficacy |
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| المؤلفون: | Lucia G. Sivilotti, Hongtao Zhu, Jie Yu, Vid Jazbec, Remigijus Lape, Josip Ivica, Matthew G. Gold, Eric Gouaux |
| المصدر: | The Journal of Biological Chemistry |
| بيانات النشر: | American Society for Biochemistry and Molecular Biology, 2021. |
| سنة النشر: | 2021 |
| مصطلحات موضوعية: | 0301 basic medicine, Agonist, Patch-Clamp Techniques, GABA Agents, Taurine, medicine.drug_class, Protein subunit, ICD, intracellular domain, Glycine, Gating, zf, zebrafish, Biochemistry, DMEM, Dulbecco’s modified Eagle’s medium, Structure-Activity Relationship, 03 medical and health sciences, Receptors, Glycine, Protein Domains, PDB, Protein Data Bank, medicine, Animals, Humans, Homomeric, 5-HT3, 5-hydroxytryptamine type 3, Amino Acid Sequence, Molecular Biology, Glycine receptor, Cells, Cultured, Zebrafish, gamma-Aminobutyric Acid, Ion channel, pLGIC, pentameric ligand-gated ion channels, 030102 biochemistry & molecular biology, Chemistry, Glycine Agents, Cell Biology, GlyR, glycine receptor, ECD, extracellular domain, Transmembrane protein, Transmembrane domain, 030104 developmental biology, beta-Alanine, Biophysics, Popen, open probability, Research Article, TM, transmembrane |
| الوصف: | Like other pentameric ligand-gated channels, glycine receptors (GlyRs) contain long intracellular domains (ICDs) between transmembrane helices 3 and 4. Structurally characterized GlyRs are generally engineered to have a very short ICD. We show here that for one such construct, zebrafish GlyREM, the agonists glycine, β-alanine, taurine, and GABA have high efficacy and produce maximum single-channel open probabilities greater than 0.9. In contrast, for full-length human α1 GlyR, taurine and GABA were clearly partial agonists, with maximum open probabilities of 0.46 and 0.09, respectively. We found that the elevated open probabilities in GlyREM are not due to the limited sequence differences between the human and zebrafish orthologs, but rather to replacement of the native ICD with a short tripeptide ICD. Consistent with this interpretation, shortening the ICD in the human GlyR increased the maximum open probability produced by taurine and GABA to 0.90 and 0.70, respectively, but further engineering it to resemble GlyREM (by introducing the zebrafish transmembrane helix 4 and C terminus) had no effect. Furthermore, reinstating the native ICD to GlyREM converted taurine and GABA to partial agonists, with maximum open probabilities of 0.66 and 0.40, respectively. Structural comparison of transmembrane helices 3 and 4 in short- and long-ICD GlyR subunits revealed that ICD shortening does not distort the orientation of these helices within each subunit. This suggests that the effects of shortening the ICD stem from removing a modulatory effect of the native ICD on GlyR gating, revealing a new role for the ICD in pentameric ligand-gated channels. |
| اللغة: | English |
| تدمد: | 1083-351X 0021-9258 |
| الوصول الحر: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::ac5e62e52b02e33fb60a4766d31b3107Test http://europepmc.org/articles/PMC7995613Test |
| حقوق: | OPEN |
| رقم الانضمام: | edsair.doi.dedup.....ac5e62e52b02e33fb60a4766d31b3107 |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 1083351X 00219258 |
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