TY - JOUR
T1 - Comparison of WNK4 and WNK1 kinase and inhibiting activities
AU - Wang, Zhaohong
AU - Yang, Chao Ling
AU - Ellison, David H.
N1 - Funding Information:
This work was supported by the NIH/NIDDK (RO1 DK51496) and by internal funds provided by OHSU. The authors thank Dr. Melanie Cobb for the WNK1 clone and antibody.
PY - 2004/5/7
Y1 - 2004/5/7
N2 - WNK kinases are novel serine/threonine protein kinases. Mutations in two members of the WNK family, WNK1 and WNK4, cause familial hyperkalemic hypertension. These kinases regulate ion transport across diverse epithelia; WNK4 reduces activity of the Na-Cl cotransporter activity and the potassium channel, ROMK, by reducing their appearance at the plasma membrane. We examined the kinase activity of WNK1 and WNK4 in vitro. A glutathione S-transferase (GST) fusion protein of the WNK1 kinse domain phosphorylated itself and a substrate protein, as reported previously. A longer construct, containing the autoinhibitory domain, did not. A GST WNK4 kinase domain construct demonstrated no kinase activity, in vitro or in HEK 293 cells. WNK4 constructs that included a region homologous to the autoinhibitory domain of WNK1 inhibited WNK1 kinase activity. Inhibition by a short WNK4 segment, WNK4 (444-518), was greater than inhibition by WNK4 (444-563). Together, these results suggest that WNK4 must be activated by currently unknown factors to exhibit kinase activity and that WNK4 contains an inhibitory domain that can inhibit the kinase activity of WNK1.
AB - WNK kinases are novel serine/threonine protein kinases. Mutations in two members of the WNK family, WNK1 and WNK4, cause familial hyperkalemic hypertension. These kinases regulate ion transport across diverse epithelia; WNK4 reduces activity of the Na-Cl cotransporter activity and the potassium channel, ROMK, by reducing their appearance at the plasma membrane. We examined the kinase activity of WNK1 and WNK4 in vitro. A glutathione S-transferase (GST) fusion protein of the WNK1 kinse domain phosphorylated itself and a substrate protein, as reported previously. A longer construct, containing the autoinhibitory domain, did not. A GST WNK4 kinase domain construct demonstrated no kinase activity, in vitro or in HEK 293 cells. WNK4 constructs that included a region homologous to the autoinhibitory domain of WNK1 inhibited WNK1 kinase activity. Inhibition by a short WNK4 segment, WNK4 (444-518), was greater than inhibition by WNK4 (444-563). Together, these results suggest that WNK4 must be activated by currently unknown factors to exhibit kinase activity and that WNK4 contains an inhibitory domain that can inhibit the kinase activity of WNK1.
KW - Chloride transport
KW - Distal convoluted tubule
KW - Distal tubule
KW - Kidney
KW - Serine/threonine kinases
KW - Sodium chloride transporter
KW - WNK kinases
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U2 - 10.1016/j.bbrc.2004.03.132
DO - 10.1016/j.bbrc.2004.03.132
M3 - Article
C2 - 15081430
AN - SCOPUS:1842689693
SN - 0006-291X
VL - 317
SP - 939
EP - 944
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
IS - 3
ER -