D184E mutation in aquaporin-4 gene impairs water permeability and links to deafness

G. P. Nicchia, R. Ficarella, A. Rossi, I. Giangreco, O. Nicolotti, A. Carotti, F. Pisani, Xavier P. Estivill, P. Gasparini, M. Svelto, A. Frigeri

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

Aquaporins (AQPs) play a physiological role in several organs and tissues, and their alteration is associated with disorders of water regulation. The identification of molecular interactions, which are crucial in determining the rate of water flux through the channel, is of pivotal role for the discovery of molecules able to target those interactions and therefore to be used for pathologies ascribable to an altered AQP-dependent water balance. In the present study, a mutational screening of human aquaporin-4 (AQP4) gene was performed on subjects with variable degrees of hearing loss. One heterozygous missense mutation was identified in a Spanish sporadic case, leading to an Asp/Glu amino acid substitution at position 184 (D184E). A BLAST analysis revealed that the amino acid D184 is conserved across species, consistently with a crucial role in the structure/function of AQP4 water channels. The mutation induces a significant reduction in water permeability as measured by the Xenopus laevis oocytes swelling assay and by the use of mammalian cells by total internal reflection microscopy. By Western blot, immunofluorescence and 2D Blue Native/SDS-PAGE we show that the reduction in water permeability is not ascribable to a reduced expression of AQP4 mutant protein or to its incorrect plasma membrane targeting and aggregation into orthogonal arrays of particles. Molecular dynamics simulation provided a molecular explanation of the mechanism whereby the mutation induces a loss of function of the channel. Substituting glutamate for aspartate affects the mobility of the D loop, which acquires a higher propensity to equilibrate in a "closed conformation", thus affecting the rate of water flux. We speculate that this mutation, combined with other genetic defects or concurrently with certain environmental stimuli, could confer a higher susceptibility to deafness.

Original languageEnglish
Pages (from-to)80-88
Number of pages9
JournalNeuroscience
Volume197
DOIs
Publication statusPublished - 1 Dec 2011
Externally publishedYes

Fingerprint

Aquaporin 4
Deafness
Permeability
Aquaporins
Mutation
Water
Genes
Native Polyacrylamide Gel Electrophoresis
Xenopus laevis
Missense Mutation
Mutant Proteins
Amino Acid Substitution
Molecular Dynamics Simulation
Hearing Loss
Aspartic Acid
Oocytes
Fluorescent Antibody Technique
Polyacrylamide Gel Electrophoresis
Glutamic Acid
Microscopy

Keywords

  • AQP4
  • Aquaporins
  • D184E
  • Deafness
  • OAPS
  • Water transport

ASJC Scopus subject areas

  • Neuroscience(all)

Cite this

Nicchia, G. P., Ficarella, R., Rossi, A., Giangreco, I., Nicolotti, O., Carotti, A., ... Frigeri, A. (2011). D184E mutation in aquaporin-4 gene impairs water permeability and links to deafness. Neuroscience, 197, 80-88. https://doi.org/10.1016/j.neuroscience.2011.09.023

D184E mutation in aquaporin-4 gene impairs water permeability and links to deafness. / Nicchia, G. P.; Ficarella, R.; Rossi, A.; Giangreco, I.; Nicolotti, O.; Carotti, A.; Pisani, F.; Estivill, Xavier P.; Gasparini, P.; Svelto, M.; Frigeri, A.

In: Neuroscience, Vol. 197, 01.12.2011, p. 80-88.

Research output: Contribution to journalArticle

Nicchia, GP, Ficarella, R, Rossi, A, Giangreco, I, Nicolotti, O, Carotti, A, Pisani, F, Estivill, XP, Gasparini, P, Svelto, M & Frigeri, A 2011, 'D184E mutation in aquaporin-4 gene impairs water permeability and links to deafness', Neuroscience, vol. 197, pp. 80-88. https://doi.org/10.1016/j.neuroscience.2011.09.023
Nicchia GP, Ficarella R, Rossi A, Giangreco I, Nicolotti O, Carotti A et al. D184E mutation in aquaporin-4 gene impairs water permeability and links to deafness. Neuroscience. 2011 Dec 1;197:80-88. https://doi.org/10.1016/j.neuroscience.2011.09.023
Nicchia, G. P. ; Ficarella, R. ; Rossi, A. ; Giangreco, I. ; Nicolotti, O. ; Carotti, A. ; Pisani, F. ; Estivill, Xavier P. ; Gasparini, P. ; Svelto, M. ; Frigeri, A. / D184E mutation in aquaporin-4 gene impairs water permeability and links to deafness. In: Neuroscience. 2011 ; Vol. 197. pp. 80-88.
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