Myosin light chains are not a physiological substrate of AMPK in the control of cell structure changes.
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.
Bultot
Laurent
L
Université Catholique de Louvain, de Duve Institute, Brussels, Belgium. laurent.bultot@uclouvain.be
Horman
Sandrine
S
Neumann
Dietbert
D
Walsh
Michael P
MP
Hue
Louis
L
Rider
Mark H
MH
D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine / Q000031:analogs & derivatives / Q000494:pharmacology; D000091162:AMP-Activated Protein Kinase Kinases; D000818:Animals; D002460:Cell Line; D004285:Dogs; D006801:Humans; D018994:Myosin Light Chains / Q000378:metabolism*; D010766:Phosphorylation; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D013379:Substrate Specificity; D054460:rho-Associated Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism
C459092:2-methyl-1-((4-methyl-5-isoquinolinyl)sulfonyl)homopiperazine; D018994:Myosin Light Chains; D047428:Protein Kinase Inhibitors; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D011494:Protein Kinases; D054460:rho-Associated Kinases; D000091162:AMP-Activated Protein Kinase Kinases