A common mechanism of defective channel trafficking underlying DFNA2 hearing loss result in different cell surface expression levels of KCNQ4 mutants

Morin, M. and Mayo, F. and Gonzalez Nieto, Daniel and Fasciani, I. and Castillo, I. del and Moreno, F. and Barrio, L. and Moreno Pelayo, M.A. (2011). A common mechanism of defective channel trafficking underlying DFNA2 hearing loss result in different cell surface expression levels of KCNQ4 mutants. In: "Jornadas de Formación CIBERER 2011", 07/11/2011 - 08/11/2011, Madrid, España.

Description

Title: A common mechanism of defective channel trafficking underlying DFNA2 hearing loss result in different cell surface expression levels of KCNQ4 mutants
Author/s:
  • Morin, M.
  • Mayo, F.
  • Gonzalez Nieto, Daniel
  • Fasciani, I.
  • Castillo, I. del
  • Moreno, F.
  • Barrio, L.
  • Moreno Pelayo, M.A.
Item Type: Presentation at Congress or Conference (Poster)
Event Title: Jornadas de Formación CIBERER 2011
Event Dates: 07/11/2011 - 08/11/2011
Event Location: Madrid, España
Title of Book: Actas del Jornadas de Formación CIBERER 2011
Date: 2011
Subjects:
Faculty: E.T.S.I. Telecomunicación (UPM)
Department: Tecnología Fotónica [hasta 2014]
Creative Commons Licenses: Recognition - No derivative works - Non commercial

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Abstract

KCNQ4 mutations underlie DFNA2, a subtype of autosomal dominant hearing loss. We had previously identified the pore-region p.G296S mutation that impaired channel activity in two manners: it greatly reduced surface expression and abolished channel function. Moreover, G296S mutant exerted a strong dominant-negative effect on potassium currents by reducing the channel expression at the cell surface representing the first study to identify a trafficking-dependent dominant mechanism for the loss of KCNQ4 channel function in DFNA2. Here, we have investigated the pathogenic mechanism associated with all the described KCNQ4 mutations (F182L, W242X, E260K, D262V, L274H, W276S, L281S, G285C, G285S and G321S) that are located in different domains of the channel protein. F182L mutant showed a wild type-like cell-surface distribution in transiently transfected NIH3T3 fibroblasts and the recorded currents in Xenopus oocytes resembled those of the wild-type. The remaining KCNQ4 mutants abolished potassium currents, but displayed distinct levels of defective cell-surface expression in NIH3T3 as quantified by flow citometry. Co-localization studies revealed these mutants were retained in the ER, unless W242X, which showed a clear co-localization with Golgi apparatus. Interestingly, this mutation results in a truncated KCNQ4 protein at the S5 transmembrane domain, before the pore region, that escapes the protein quality control in the ER but does not reach the cell surface at normal levels. Currently we are investigating the trafficking behaviour and electrophysiological properties of several KCNQ4 truncated proteins artificially generated in order to identify specific motifs involved in channel retention/exportation. Altogether, our results indicate that a defect in KCNQ4 trafficking is the common mechanism underlying DFNA2

More information

Item ID: 13598
DC Identifier: http://oa.upm.es/13598/
OAI Identifier: oai:oa.upm.es:13598
Deposited by: Memoria Investigacion
Deposited on: 21 Nov 2012 12:11
Last Modified: 21 Apr 2016 12:56
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