Anion conductance of the human red cell is carried by a maxi-anion channel.
Historically, the anion transport through the human red cell membrane has been perceived to be mediated by Band 3, in the two-component concept with the large electroneutral anion exchange accompanied by the conductance proper, which dominated the total membrane conductance. The status of anion channels proper has never been clarified, and the informations obtained by different groups of electrophysiologists are rather badly matched. This study, using the cell-attached configuration of the patch-clamp technique, rationalizes and explains earlier confusing results by demonstrating that the diversity of anionic channel activities recorded in human erythrocytes corresponds to different kinetic modalities of a unique type of maxi-anion channel with multiple conductance levels and probably multiple gating properties and pharmacology, depending on conditions. It demonstrates the role of activator played by serum in the recruitment of multiple new conductance levels showing very complex kinetics and gating properties upon serum addition. These channels, which seem to be dormant under normal physiological conditions, are potentially activable and could confer a far higher anion conductance to the red cell than the ground leak mediated by Band 3.
Glogowska
Edyta
E
Centre National de la Recherche Scientifique, Université Pierre et Marie Curie Paris6, UMR 7150, Station Biologique, B. P. 74, 29682 Roscoff cedex, France.
Dyrda
Agnieszka
A
Cueff
Anne
A
Bouyer
Guillaume
G
Egée
Stéphane
S
Bennekou
Poul
P
Thomas
Serge L Y
SL
D001457:Anion Exchange Protein 1, Erythrocyte / Q000502:physiology; D018118:Chloride Channels / Q000097:blood* / Q000502:physiology; D002712:Chlorides / Q000097:blood; D016895:Culture Media, Serum-Free / Q000494:pharmacology; D004912:Erythrocytes / Q000378:metabolism*; D006801:Humans; D015640:Ion Channel Gating; D009579:Nitrobenzoates / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D044967:Serum; D013861:Thiocyanates / Q000378:metabolism / Q000494:pharmacology; D015854:Up-Regulation
D001457:Anion Exchange Protein 1, Erythrocyte; D018118:Chloride Channels; D002712:Chlorides; D016895:Culture Media, Serum-Free; D009579:Nitrobenzoates; C454201:SLC4A1 protein, human; D013861:Thiocyanates; C058176:5-nitro-2-(3-phenylpropylamino)benzoic acid; C024553:sodium thiocyanate