The NH(2)-terminus of K(+)-Cl(-) cotransporter 3a is essential for up-regulation of Na(+),K(+)-ATPase activity.
K(+)-Cl(-) cotransporter-3 has two major amino terminal variants, KCC3a and KCC3b. In LLC-PK1 cells, exogenously expressed KCC3a co-immunoprecipitated with endogenous Na(+),K(+)-ATPase alpha1-subunit (alpha1NaK), accompanying significant increases of the Na(+),K(+)-ATPase activity. Exogenously expressed KCC3b did not co-immunoprecipitate with endogenous alpha1NaK inducing no change of the Na(+),K(+)-ATPase activity. A KCC inhibitor attenuated the Na(+),K(+)-ATPase activity in rat gastric mucosa in which KCC3a is predominantly expressed, while it had no effects on the Na(+),K(+)-ATPase activity in rat kidney in which KCC3b is predominantly expressed. In these tissue samples, KCC3a co-immunoprecipitated with alpha1NaK, while KCC3b did not. Our results suggest that the NH(2)-terminus of KCC3a is a key region for association with alpha1NaK, and that KCC3a but not KCC3b can regulate the Na(+),K(+)-ATPase activity.
Fujii
Takuto
T
Department of Pharmaceutical Physiology, University of Toyama, Toyama 930-0194, Japan. fujiitk@pha.u-toyama.ac.jp
Fujita
Kyosuke
K
Shimizu
Takahiro
T
Takeguchi
Noriaki
N
Sakai
Hideki
H
D000818:Animals; D002460:Cell Line; D005753:Gastric Mucosa / Q000378:metabolism; D047468:Immunoprecipitation; D007668:Kidney / Q000378:metabolism; D017434:Protein Structure, Tertiary; D051381:Rats; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D027981:Symporters / Q000235:genetics / Q000378:metabolism*; D013752:Tetracycline / Q000494:pharmacology; D015854:Up-Regulation; D000096922:K Cl- Cotransporters
D000254:Sodium-Potassium-Exchanging ATPase; D027981:Symporters; D013752:Tetracycline; C492281:Slc12a6 protein, rat; D000096922:K Cl- Cotransporters; C499075:Atp1a1 protein, rat