ICln channels reconstituted in heart-lipid bilayer are selective to chloride.
ICln is an ion channel cloned from renal epithelial cells. The reconstitution of the protein in 1,2-diphytanoyl- sn-glycero-3-phosphocholine (Diph-PC) bilayer membranes reveals potassium-selective channels, which become more chloride selective in the presence of calcium. Here we show that the ion selectivity of ICln also depends on the lipid environment in which the channels are reconstituted. Diph-PC is a synthetic lipid commonly used for reconstituting ion channels. However, since this lipid is not found in native membranes, we reconstituted the ICln ion channels in a polar heart-lipid extract. Using this lipid mixture the reconstituted ICln ion channels are chloride selective in the presence of calcium and an acidic pH. The relative ion selectivity of ICln under these conditions is similar to the cation versus anion selectivity of native ion channels activated by cell swelling.
Garavaglia
Maria Lisa
ML
Institute of Physiology, University of Innsbuck, Austria.
Rodighiero
Simona
S
Bertocchi
Christina
C
Manfredi
Rosangela
R
Fürst
Johannes
J
Gschwentner
Martin
M
Ritter
Markus
M
Bazzini
Claudia
C
Bottà
Guido
G
Jakab
Martin
M
Meyer
Giuliano
G
Paulmichl
Markus
M
D000143:Acids / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002712:Chlorides / Q000493:pharmacokinetics*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D015640:Ion Channel Gating / Q000187:drug effects / Q000502:physiology; D007473:Ion Channels; D008051:Lipid Bilayers / Q000378:metabolism*; D008274:Magnesium / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D009206:Myocardium / Q000378:metabolism*; D010713:Phosphatidylcholines / Q000494:pharmacology*; D011506:Proteins / Q000502:physiology*
D000143:Acids; C410035:CLNS1A protein, human; D002712:Chlorides; D007473:Ion Channels; D008051:Lipid Bilayers; D010713:Phosphatidylcholines; D011506:Proteins; C021016:1,2-diphytanoylphosphatidylcholine; D008274:Magnesium; D002118:Calcium