U-0126 is a MEK inhibitor with IC
50 values of 72 nM and 58 nM for MEK1 and MEK2, respectively.
1 It is noncompetitive with respect adenosine triphosphate (ATP) and its phosphorylation target ERK and it shows little to no inhibition against a number of other kinases including PKC, Ab1, Raf, MEKK, ERK, JNK, MKK-3, MKK-4, MKK-6, Cdk2, and Cdk4. However, U-0126 does phosphorylate and activate AMP-activated protein kinase (AMPK) in a dose-dependent manner (EC
50 = 15 μM in HEK293 cells).
2 It increases the ratios of ADP to ATP and AMP to ATP and increases phosphorylation of the AMPK target acetyl-CoA carboxylase (ACC).