P2X2 Dominant Deafness Mutations Have No Negative Effect on Wild-Type Isoform: Implications for Functional Rescue and in Deafness Mechanism
The P2X2 receptor is an ATP-gated ion channel, assembled by three subunits. Recently, it has been found that heterozygous mutations of P2X2 V60L and G353R can cause autosomal dominant nonsyndromic hearing loss. However, the underlying mechanism remains unclear. The fact that heterozygous mutations c...
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| Format: | Article |
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Frontiers Media S.A.
2017-11-01
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| Series: | Frontiers in Molecular Neuroscience |
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| Online Access: | http://journal.frontiersin.org/article/10.3389/fnmol.2017.00371/full |
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| author | Yan Zhu Juline Beudez Juline Beudez Ning Yu Ning Yu Thomas Grutter Thomas Grutter Hong-Bo Zhao |
| author_facet | Yan Zhu Juline Beudez Juline Beudez Ning Yu Ning Yu Thomas Grutter Thomas Grutter Hong-Bo Zhao |
| author_sort | Yan Zhu |
| collection | DOAJ |
| description | The P2X2 receptor is an ATP-gated ion channel, assembled by three subunits. Recently, it has been found that heterozygous mutations of P2X2 V60L and G353R can cause autosomal dominant nonsyndromic hearing loss. However, the underlying mechanism remains unclear. The fact that heterozygous mutations cause deafness suggests that the mutations may have dominant-negative effect (DNE) on wild-type (WT) P2X2 isoforms and/or other partners leading to hearing loss. In this study, the effect of these dominant deafness P2X2 mutations on WT P2X2 was investigated. We found that sole transfection of both V60L and G353R deafness mutants could efficiently target to the plasma membrane, like WT P2X2, but exhibit a significantly reduced response to ATP stimulation. Both mutants reduced the channel conductance, but G353R mutation also altered the voltage dependency. Co-expression with WT P2X2 could restore the response to ATP. As the ratio of WT P2X2 vs. mutants increased, the response to ATP was also increased. Computer modeling confirmed that both V60L and G353R dominant-deafness mutant subunits do not have any negative effect on WT P2X2 subunit, when assembled as a heterotrimer. Improper docking or defective gating is the more likely mechanism for impaired channel function by these P2X2 deafness mutations. These results suggest that P2X2 dominant deafness mutations do not have negative effects on WT P2X2 isoforms, and that adding additional WT P2X2 could rescue the lost channel function caused by the deafness mutations. These P2X2 dominant deafness mutations may have negative-effects on other partners leading to hearing loss. |
| first_indexed | 2024-12-23T20:55:46Z |
| format | Article |
| id | doaj.art-3e8a36d0f4344ee69a1b73885c593604 |
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| issn | 1662-5099 |
| language | English |
| last_indexed | 2024-12-23T20:55:46Z |
| publishDate | 2017-11-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Molecular Neuroscience |
| spelling | doaj.art-3e8a36d0f4344ee69a1b73885c5936042022-12-21T17:31:31ZengFrontiers Media S.A.Frontiers in Molecular Neuroscience1662-50992017-11-011010.3389/fnmol.2017.00371305377P2X2 Dominant Deafness Mutations Have No Negative Effect on Wild-Type Isoform: Implications for Functional Rescue and in Deafness MechanismYan Zhu0Juline Beudez1Juline Beudez2Ning Yu3Ning Yu4Thomas Grutter5Thomas Grutter6Hong-Bo Zhao7Department of Otolaryngology, University of Kentucky Medical Center, Lexington, KY, United StatesCentre National de la Recherche Scientifique, Unité Mixte de Recherche 7199, Laboratoire de Conception et Application de Molécules Bioactives, Équipe de Chimie et Neurobiologie Moléculaire, Strasbourg, FranceFaculté de Pharmacie, Université de Strasbourg, Strasbourg, FranceDepartment of Otolaryngology, University of Kentucky Medical Center, Lexington, KY, United StatesDepartment of Otolaryngology, Institute of Otolaryngology, Chinese PLA General Hospital, Beijing, ChinaCentre National de la Recherche Scientifique, Unité Mixte de Recherche 7199, Laboratoire de Conception et Application de Molécules Bioactives, Équipe de Chimie et Neurobiologie Moléculaire, Strasbourg, FranceFaculté de Pharmacie, Université de Strasbourg, Strasbourg, FranceDepartment of Otolaryngology, University of Kentucky Medical Center, Lexington, KY, United StatesThe P2X2 receptor is an ATP-gated ion channel, assembled by three subunits. Recently, it has been found that heterozygous mutations of P2X2 V60L and G353R can cause autosomal dominant nonsyndromic hearing loss. However, the underlying mechanism remains unclear. The fact that heterozygous mutations cause deafness suggests that the mutations may have dominant-negative effect (DNE) on wild-type (WT) P2X2 isoforms and/or other partners leading to hearing loss. In this study, the effect of these dominant deafness P2X2 mutations on WT P2X2 was investigated. We found that sole transfection of both V60L and G353R deafness mutants could efficiently target to the plasma membrane, like WT P2X2, but exhibit a significantly reduced response to ATP stimulation. Both mutants reduced the channel conductance, but G353R mutation also altered the voltage dependency. Co-expression with WT P2X2 could restore the response to ATP. As the ratio of WT P2X2 vs. mutants increased, the response to ATP was also increased. Computer modeling confirmed that both V60L and G353R dominant-deafness mutant subunits do not have any negative effect on WT P2X2 subunit, when assembled as a heterotrimer. Improper docking or defective gating is the more likely mechanism for impaired channel function by these P2X2 deafness mutations. These results suggest that P2X2 dominant deafness mutations do not have negative effects on WT P2X2 isoforms, and that adding additional WT P2X2 could rescue the lost channel function caused by the deafness mutations. These P2X2 dominant deafness mutations may have negative-effects on other partners leading to hearing loss.http://journal.frontiersin.org/article/10.3389/fnmol.2017.00371/fullP2X2 receptormutationdeafnessdominant negative effectfunctional restorationATP |
| spellingShingle | Yan Zhu Juline Beudez Juline Beudez Ning Yu Ning Yu Thomas Grutter Thomas Grutter Hong-Bo Zhao P2X2 Dominant Deafness Mutations Have No Negative Effect on Wild-Type Isoform: Implications for Functional Rescue and in Deafness Mechanism Frontiers in Molecular Neuroscience P2X2 receptor mutation deafness dominant negative effect functional restoration ATP |
| title | P2X2 Dominant Deafness Mutations Have No Negative Effect on Wild-Type Isoform: Implications for Functional Rescue and in Deafness Mechanism |
| title_full | P2X2 Dominant Deafness Mutations Have No Negative Effect on Wild-Type Isoform: Implications for Functional Rescue and in Deafness Mechanism |
| title_fullStr | P2X2 Dominant Deafness Mutations Have No Negative Effect on Wild-Type Isoform: Implications for Functional Rescue and in Deafness Mechanism |
| title_full_unstemmed | P2X2 Dominant Deafness Mutations Have No Negative Effect on Wild-Type Isoform: Implications for Functional Rescue and in Deafness Mechanism |
| title_short | P2X2 Dominant Deafness Mutations Have No Negative Effect on Wild-Type Isoform: Implications for Functional Rescue and in Deafness Mechanism |
| title_sort | p2x2 dominant deafness mutations have no negative effect on wild type isoform implications for functional rescue and in deafness mechanism |
| topic | P2X2 receptor mutation deafness dominant negative effect functional restoration ATP |
| url | http://journal.frontiersin.org/article/10.3389/fnmol.2017.00371/full |
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