The NH(2)-terminus of K(+)-Cl(-) cotransporter 3a is essential for up-regulation of Na(+),K(+)-ATPase activity.

Takuto Fujii, Kyosuke Fujita, Takahiro Shimizu, Noriaki Takeguchi, Hideki Sakai

Department of Pharmaceutical Physiology, University of Toyama, Toyama 930-0194, Japan. fujiitk@pha.u-toyama.ac.jp

Biochemical and biophysical research communications 2010 Sep 3

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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. Copyright 2010 Elsevier Inc. All rights reserved.

Citation

Takuto Fujii, Kyosuke Fujita, Takahiro Shimizu, Noriaki Takeguchi, Hideki Sakai. The NH(2)-terminus of K(+)-Cl(-) cotransporter 3a is essential for up-regulation of Na(+),K(+)-ATPase activity. Biochemical and biophysical research communications. 2010 Sep 3;399(4):683-7