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Src‐family protein tyrosine kinase (SFK) stimulates KCNJ10 K channels in the basolateral membrane of distal convoluted tubules (DCT).
Author(s) -
Wang WenHui,
Zhang ChengBiao,
Lin DaoHong,
Yue Peng,
Wang Lijun,
Rinehart Jesse
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.911.1
Subject(s) - phosphorylation , tyrosine phosphorylation , tyrosine , proto oncogene tyrosine protein kinase src , biology , microbiology and biotechnology , cotransporter , transfection , chemistry , endocrinology , medicine , cell culture , biochemistry , genetics , organic chemistry , sodium
The basolateral K channels in the DCT are composed of KCNJ10 and KCNJ16. Since KCNJ10 have several SFK‐consensus phosphorylation sites (Tyr 8, 9, 51 & 349), we tested the role of tyrosine phosphorylation in regulating KCNJ10. The patch‐clamp experiments were performed in HEK cells transfected with GFP‐tagged KCNJ10 and in the mouse DCT1. Suppression of SFK with PP1 reversibly inhibited the basolateral 40 pS K channels in cell‐attached mode and decreased the whole cell K currents in DCT1 cells. Western blot shows that KCNJ10 is a tyrosine phosphorylated protein. GC‐MASS confirmed that Tyr 8 & 9 were phosphorylated in KCNJ10 protein harvested from HEK293 cells. Mutation of Tyr 9 to phenyalanine decreased the whole cell K currents by 60% while mutations of Tyr 8, 51 and 349 had no significant effect on the whole‐cell K currents. To examine the physiological role of tyrosine phosphorylation of KCNJ10 in DCT1, we measured the whole‐cell K currents in the DCT1 from mice on a high K diet (HK) which is know to decrease SFK activity. The whole cell K current in DCT1 of mice on HK was significantly smaller than those of control animals. We conclude that Tyr 9 is a tyrosine phosphorylation site and that dephosphorylation of Tyr9 inhibited the KCNJ10 activity. We speculate that a decrease in basolateral K channels in DCT1 in mice on HK diminished the basolateral Cl exit thereby decreasing NaCl transport in DCT1.