The protein kinase C inhibitors bisindolylmaleimide I (GF 109203x) and IX (Ro 31-8220) are potent inhibitors of glycogen synthase kinase-3 activity.
Here we report that the widely used protein kinase C inhibitors, bisindolylmaleimide I and IX, are potent inhibitors of glycogen synthase kinase-3 (GSK-3). Bisindolylmaleimide I and IX inhibited GSK-3 in vitro, when assayed either in cell lysates (IC(50) 360 nM and 6.8 nM, respectively) or in GSK-3beta immunoprecipitates (IC(50) 170 nM and 2.8 nM, respectively) derived from rat epididymal adipocytes. Pretreatment of adipocytes with bisindolylmaleimide I (5 microM) and IX (2 microM) reduced GSK-3 activity in total cell lysates, to 25.1+/-4.3% and 12.9+/-3.0% of control, respectively. By contrast, bisindolylmaleimide V (5 microM), which lacks the functional groups present on bisindolylmaleimide I and IX, had little apparent effect. We propose that bisindolylmaleimide I and IX can directly inhibit GSK-3, and that this may explain some of the previously reported insulin-like effects on glycogen synthase activity.
Hers
I
I
Department of Biochemistry, School of Medical Sciences, University of Bristol, UK. i.hers@bris.ac.uk
Tavaré
J M
JM
Denton
R M
RM
D017667:Adipocytes / Q000187:drug effects / Q000201:enzymology; D000818:Animals; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000037:antagonists & inhibitors*; D002478:Cells, Cultured; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D038362:Glycogen Synthase Kinase 3; D038341:Glycogen Synthase Kinases; D007211:Indoles / Q000494:pharmacology*; D008297:Male; D008301:Maleimides / Q000494:pharmacology*; D008869:Microtubule-Associated Proteins / Q000037:antagonists & inhibitors; D011493:Protein Kinase C / Q000037:antagonists & inhibitors*; D051381:Rats; D017208:Rats, Wistar
D004791:Enzyme Inhibitors; D007211:Indoles; D008301:Maleimides; D008869:Microtubule-Associated Proteins; D038341:Glycogen Synthase Kinases; D011493:Protein Kinase C; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D038362:Glycogen Synthase Kinase 3; C070515:bisindolylmaleimide I; C064758:Ro 31-8220