Activation of AMPK reduces the co-transporter activity of NKCC1 |
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Authors: | Scott A Fraser Matthew Davies Marina Katerelos Kurt Gleich Suet-Wan Choy Rohan Steel |
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Institution: | 1. Institute for Breathing and Sleep, Kidney Laboratory
Melbourne, Australia;2. Department of Nephrology, Austin Health
Heidelberg, Australia;3. Department of Medicine, Austin Health, University of Melbourne
Victoria, Australia;4. St. Vincent’s Institute
Fitzroy, VictoriaAustralia |
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Abstract: | The co-transporter activity of Na+-K+-2Cl? 1 (NKCC1) is dependent on phosphorylation. In this study we show the energy-sensing kinase AMPK inhibits NKCC1 activity. Three separate AMPK activators (AICAR, Phenformin and A-769662) inhibited NKCC1 flux in a variety of nucleated cells. Treatment with A-769662 resulted in a reduction of NKCC1T212/T217 phosphorylation, and this was reversed by treatment with the non-selective AMPK inhibitor Compound C. AMPK dependence was confirmed by treatment of AMPK null mouse embryonic fibroblasts, where A-769662 had no effect on NKCC1 mediated transport. AMPK was found to directly phosphorylate a recombinant human-NKCC1 N-terminal fragment (1–293) with the phosphorylated site identified as S77. Mutation of Serine 77 to Alanine partially prevented the inhibitory effect of A-769662 on NKCC1 activity. In conclusion, AMPK can act to reduce NKCC1-mediated transport. While the exact mechanism is still unclear there is evidence for both a direct effect on phosphorylation of S77 and reduced phosphorylation of T212/217. |
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Keywords: | Cell biology epithelial cell Na-coupled transport |
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