caa a22 4500 445883871 CHVBK 20180317145553.0 cr unu---uuuuu 170323e20110401xx s 000 0 eng 10.1007/s10157-010-0378-9 doi (NATIONALLICENCE)springer-10.1007/s10157-010-0378-9 Regulation of WNK1 kinase by extracellular potassium [Elektronische Daten] [Shotaro Naito, Akihito Ohta, Eisei Sohara, Eriko Ohta, Tatemitsu Rai, Sei Sasaki, Shinichi Uchida] Background: Mutations of WNK kinase genes were identified as the cause of a hereditary hypertensive disease, pseudohypoaldosteronism type II; however, little is known about the regulation of WNK kinases. In the present study, we focused on anisosmotic conditions as the initial clues for clarifying a stimulating factor for WNK kinase activity. Methods: Endogenous WNK kinase activity in COS7 cells was monitored by the phosphorylation of its substrate, OSR1. Results: Knockdown experiments revealed that WNK1 was a major WNK kinase in COS7 cells. In contrast to the transient increase in WNK1 activity caused by hypertonic medium, hypotonic medium increased the phosphorylation of OSR1 for 24h, suggesting that the hypotonic medium included a signal for continuously stimulating WNK1 kinase activity. To identify the signal, ion substitution experiments were performed. Surprisingly, even isotonic media with low Cl− or low K+ was found to increase OSR1 phosphorylation as well as the hypotonic medium. Furthermore, WNK1 activation by the hypotonic medium was completely blocked by quinine (500μM) but not by 5-nitro-2-(3-phenylpropylamino) benzoic acid (100μM), and this inhibition was closely correlated with the inhibition of 86Rb+ (=K+) efflux but not with the inhibition of 125I− (=Cl−) efflux. These results suggest that K+, rather than hypotonicity or low Cl−, may be an important regulator for WNK1 activation. Finally, we confirmed that high K+ and low K+ media under the physiological range decreased and increased WNK1 activity, respectively. Conclusion: Extracellular K+ is an important regulator of WNK1 kinase activity. Japanese Society of Nephrology, 2010 Kinase nationallicence Potassium nationallicence COS7 cell nationallicence Quinine nationallicence Naito Shotaro Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, 113-8519, Tokyo, Bunkyo, Japan aut Ohta Akihito Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, 113-8519, Tokyo, Bunkyo, Japan aut Sohara Eisei Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, 113-8519, Tokyo, Bunkyo, Japan aut Ohta Eriko Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, 113-8519, Tokyo, Bunkyo, Japan aut Rai Tatemitsu Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, 113-8519, Tokyo, Bunkyo, Japan aut Sasaki Sei Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, 113-8519, Tokyo, Bunkyo, Japan aut Uchida Shinichi Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, 113-8519, Tokyo, Bunkyo, Japan aut Clinical and Experimental Nephrology Springer Japan 15/2(2011-04-01), 195-202 1342-1751 15:2<195 2011 15 10157 https://doi.org/10.1007/s10157-010-0378-9 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10157-010-0378-9 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Naito Shotaro Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, 113-8519, Tokyo, Bunkyo, Japan aut NATIONALLICENCE 700 1- Ohta Akihito Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, 113-8519, Tokyo, Bunkyo, Japan aut NATIONALLICENCE 700 1- Sohara Eisei Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, 113-8519, Tokyo, Bunkyo, Japan aut NATIONALLICENCE 700 1- Ohta Eriko Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, 113-8519, Tokyo, Bunkyo, Japan aut NATIONALLICENCE 700 1- Rai Tatemitsu Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, 113-8519, Tokyo, Bunkyo, Japan aut NATIONALLICENCE 700 1- Sasaki Sei Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, 113-8519, Tokyo, Bunkyo, Japan aut NATIONALLICENCE 700 1- Uchida Shinichi Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, 113-8519, Tokyo, Bunkyo, Japan aut NATIONALLICENCE 773 0- Clinical and Experimental Nephrology Springer Japan 15/2(2011-04-01), 195-202 1342-1751 15:2<195 2011 15 10157 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer