Role of TASK2 potassium channels regarding volume regulation in primary cultures of mouse proximal tubules.
Several papers reported the role of TASK2 channels in cell volume regulation and regulatory volume decrease (RVD). To check the possibility that the TASK2 channel modulates the RVD process in kidney, we performed primary cultures of proximal convoluted tubules (PCT) and distal convoluted tubules (DCT) from wild-type and TASK2 knockout (KO) mice. In KO mice, the TASK2 coding sequence was in part replaced by the lac-Z gene. This allows for the precise localization of TASK2 in kidney sections using beta-galactosidase staining. TASK2 was only localized in PCT cells. K+ currents were analyzed by the whole-cell clamp technique with 125 mM K-gluconate in the pipette and 140 mM Na-gluconate in the bath. In PCT cells from wild-type mice, hypotonicity induced swelling-activated K+ currents insensitive to 1 mM tetraethylammonium, 10 nM charybdotoxin, and 10 microM 293B, but blocked by 500 microM quinidine and 10 microM clofilium. These currents were increased in alkaline pH and decreased in acidic pH. In PCT cells from TASK2 KO, swelling-activated K+ currents were completely impaired. In conclusion, the TASK2 channel is expressed in kidney proximal cells and could be the swelling-activated K+ channel responsible for the cell volume regulation process during osmolyte absorptions in the proximal tubules.
Barriere
Herve
H
UMR CNRS 6548, Université de Nice-Sophia Antipolis, 06108 Nice Cedex 2, France.
Belfodil
Radia
R
Rubera
Isabelle
I
Tauc
Michel
M
Lesage
Florian
F
Poujeol
Chantal
C
Guy
Nicolas
N
Barhanin
Jacques
J
Poujeol
Philippe
P
D000818:Animals; D048429:Cell Size / Q000187:drug effects; D002478:Cells, Cultured; D007038:Hypotonic Solutions; D007687:Kidney Tubules, Proximal / Q000166:cytology* / Q000378:metabolism*; D008564:Membrane Potentials / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009995:Osmosis / Q000502:physiology*; D009997:Osmotic Pressure; D015221:Potassium Channels / Q000172:deficiency / Q000378:metabolism*; D024683:Potassium Channels, Tandem Pore Domain
D007038:Hypotonic Solutions; C498739:Kcnk5 protein, mouse; D015221:Potassium Channels; D024683:Potassium Channels, Tandem Pore Domain