Activation of AMPK reduces the co-transporter activity of NKCC1. (March 2014)

• Record Type: Journal Article
• Authors: Fraser, Scott A.; Davies, Matthew; Katerelos, Marina; Gleich, Kurt; Choy, Suet-Wan; Steel, Rohan; Galic, Sandra; Mount, Peter F.; Kemp, Bruce E.; Power, David A.
• Is Part Of: Molecular membrane biology. Volume 31:Number 2/3(2014)
• Page Start: 95
• Page End: 102
• Publication Date: 2014-03
• Subjects: Membranes (Biology) -- Periodicals; Biochemistry -- Periodicals; Cell membranes -- Periodicals; Molecular biology -- Periodicals; 571.64
• DOI: 10.3109/09687688.2014.902128
• Languages: English
• ISSNs: 0968-7688

Abstract

<abstract> <title>Abstract</title> <p>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 NKCC1^T212/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.</p> </abstract>