Myosin light chains are not a physiological substrate of AMPK in the control of cell structure changes

Bultot, Laurent; Horman, Sandrine; Neumann, Dietbert; Walsh, Michael P.; Hue, Louis; Rider, Mark H.

doi:10.1016/j.febslet.2008.11.022

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Volume 583, Issue 1 , Pages 25-28, 5 January 2009

Myosin light chains are not a physiological substrate of AMPK in the control of cell structure changes

Edited by Berend Wieringa

Laurent Bultot
- Université Catholique de Louvain, Hormone and Metabolic Research Unit, de Duve Institute, Avenue Hippocrate, 75, B-1200 Brussels, Belgium
- Corresponding author. Fax: +32 2 764 7507.
Sandrine Horman
- Université Catholique de Louvain, Hormone and Metabolic Research Unit, de Duve Institute, Avenue Hippocrate, 75, B-1200 Brussels, Belgium
- Université Catholique de Louvain, CARD Unit, Division of Cardiology, Avenue Hippocrate, 55, B-1200 Brussels, Belgium
Dietbert Neumann
- Institute of Cell Biology, Swiss Federal Institute of Technology (ETH), CH-8093 Zurich, Switzerland
Michael P. Walsh
- Smooth Muscle Research Group and Department of Biochemistry and Molecular Biology, University of Calgary, Faculty of Medicine, Calgary, Alberta, Canada T2N 4N1.
Louis Hue
- Université Catholique de Louvain, Hormone and Metabolic Research Unit, de Duve Institute, Avenue Hippocrate, 75, B-1200 Brussels, Belgium
Mark H. Rider
- Université Catholique de Louvain, Hormone and Metabolic Research Unit, de Duve Institute, Avenue Hippocrate, 75, B-1200 Brussels, Belgium

Received 29 September 2008; received in revised form 24 October 2008; accepted 4 November 2008. published online 03 December 2008.

Abstract

The kinetics of myosin regulatory light chain (MLC) phosphorylation by recombinant AMP-activated protein kinase (AMPK) were compared with commercial AMPK from rat liver and smooth muscle myosin light chain kinase (smMLCK). With identical amounts of activity units, initial rates of phosphorylation of MLC were at least 100-fold less with recombinant AMPK compared to smMLCK, whereas with rat liver AMPK significant phosphorylation was seen. In Madin-Darby Canine Kidney cells, AMPK activation led to an increase in MLC phosphorylation, which was decreased by a Rho kinase inhibitor without affecting AMPK activation. Therefore, MLC phosphorylation during energy deprivation does not result from direct phosphorylation by AMPK.