Phosphorylation and inactivation of HMG-CoA reductase at the AMP-activated protein kinase site in response to fructose treatment of isolated rat hepatocytes.
We have previously shown that incubation of isolated hepatocytes with fructose leads to elevation of AMP and activation of the AMP-activated protein kinase. We now show that this treatment causes marked inactivation of HMG-CoA reductase. Using immunoprecipitation from the microsomal fraction of 32P-labelled cells, we also show that this treatment leads to a 2.6-fold increase in the phosphorylation of the 100 kDa subunit of HMG-CoA reductase. Successive digestion of this 32P-labelled subunit with cyanogen bromide and endoproteinase Lys-C confirmed that Ser-871, the site phosphorylated in cell-free assays by the AMP-activated protein kinase, was the only site phosphorylated under these conditions.
Gillespie
J G
JG
Department of Biochemistry, The University, Dundee, Scotland, UK.
Hardie
D G
DG
D000818:Animals; D001345:Autoradiography; D001665:Binding Sites; D015153:Blotting, Western; D002478:Cells, Cultured; D003488:Cyanogen Bromide; D010450:Endopeptidases; D004789:Enzyme Activation; D005632:Fructose / Q000494:pharmacology*; D006903:Hydroxymethylglutaryl CoA Reductases / Q000378:metabolism*; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D007525:Isoelectric Focusing; D008099:Liver / Q000187:drug effects / Q000201:enzymology*; D008297:Male; D008666:Metalloendopeptidases; D010766:Phosphorylation; D011233:Precipitin Tests; D011494:Protein Kinases / Q000378:metabolism*; D051381:Rats; D012694:Serine / Q000378:metabolism
D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D005632:Fructose; D012694:Serine; D006903:Hydroxymethylglutaryl CoA Reductases; D011494:Protein Kinases; D010450:Endopeptidases; D008666:Metalloendopeptidases; C039830:peptidyl-Lys metalloendopeptidase; D003488:Cyanogen Bromide