Abstract
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.
Document Type
Article
Publication Date
11-13-2017
Digital Object Identifier (DOI)
https://doi.org/10.3389/fnmol.2017.00371
Funding Information
This work was supported by NIH R01 DC 05989 and R56 DC 015019 to H-BZ and the Agence Nationale de la Recherche (ANR-14-CE11-0004-01) to TG. NY was supported by Major State Basic Research Development Program of China (No. 2014CB943002) and National Natural Science Foundation of China (No. 81470700).
Repository Citation
Zhu, Yan; Beudez, Juline; Yu, Ning; Grutter, Thomas; and Zhao, Hong-Bo, "P2X2 Dominant Deafness Mutations Have No Negative Effect on Wild-Type Isoform: Implications for Functional Rescue and in Deafness Mechanism" (2017). Otolaryngology--Head & Neck Surgery Faculty Publications. 8.
https://uknowledge.uky.edu/otolaryngology_facpub/8
Notes/Citation Information
Published in Frontiers in Molecular Neuroscience, v. 10, 371, p. 1-10.
© 2017 Zhu, Beudez, Yu, Grutter and Zhao.
This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.