The expression of wild-type pendrin (SLC26A4) in human embryonic kidney (HEK 293 Phoenix) cells leads to the activation of cationic currents.
OBJECTIVE
The SLC26A4 protein (pendrin) seems to be involved in the exchange of chloride with other anions, therefore being responsible for iodide organification in the thyroid gland and the conditioning of the endolymphatic fluid in the inner ear. Malfunction of SLC26A4 leads to Pendred syndrome, characterized by mild thyroid dysfunction often associated with goiter and/or prelingual deafness. The precise function of the SLC26A4 protein, however, is still elusive. An open question is still whether the SLC26A4-induced ion exchange mechanism is electrogenic or electroneutral. Recently, it has been shown that human pendrin expressed in monkey cells leads to chloride currents.


METHODS
We overexpressed the human SLC26A4 isoform in HEK293 Phoenix cells and measured cationic and anionic currents by the patch-clamp technique in whole cell configuration.


RESULTS
Here we show that human pendrin expressed in human cells does not lead to the activation of chloride currents, but, in contrast, leads to an increase of cationic currents.


CONCLUSIONS
Our experiments suggest that the SLC26A4-induced chloride transport is electroneutral when expressed in human cellular systems.
Dossena
Silvia
S
Department of Biomolecular Sciences and Biotechnology, Università degli Studi di Milano,Via Celoria 26, I-20133 Milan, Italy.
Maccagni
Antonella
A
Vezzoli
Valeria
V
Bazzini
Claudia
C
Garavaglia
Maria Lisa
ML
Meyer
Giuliano
G
Fürst
Johannes
J
Ritter
Markus
M
Fugazzola
Laura
L
Persani
Luca
L
Zorowka
Patrick
P
Storelli
Carlo
C
Beck-Peccoz
Paolo
P
Bottà
Guido
G
Paulmichl
Markus
M
D002412:Cations / Q000378:metabolism*; D002460:Cell Line; D018118:Chloride Channels / Q000502:physiology; D004553:Electric Conductivity; D006801:Humans; D007473:Ion Channels / Q000502:physiology*; D026901:Membrane Transport Proteins / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D024642:Potassium Channels, Voltage-Gated / Q000502:physiology; D000076988:Sulfate Transporters
D002412:Cations; D018118:Chloride Channels; D007473:Ion Channels; D026901:Membrane Transport Proteins; D024642:Potassium Channels, Voltage-Gated; C085609:SLC26A4 protein, human; D000076988:Sulfate Transporters