ERK inhibitor is a cell-permeable inhibitor that binds ERK2 near its docking domain (KD = 5 μM). This prevents its interaction with protein substrates without inhibiting catalytic activity. ERK inhibitor blocks ERK-specific phosphorylation of ribosomal S6 kinase-1 and ternary complex factor Elk-1 but does not affect ERK1/2 phosphorylation by MEK1/2. Presumably through its effects on ERK, ERK inhibitor completely prevents proliferation of HeLa cells (IC50 = 15-20 μM), A549 lung carcinoma cells (IC50 = 25 μM), Sum-159 estrogen receptor-negative breast cancer cells and HT1080 fibrosarcoma cells.
ERK-IN-4 is an ERK inhibitor binds preferentially to ERK2 with a Kd of 5 μM. ERK-IN-4 specificity inhibits ERK Rsk-1 and Elk-1 phosphorylation. ERK-IN-4 has little effect on ERK protein phosphorylation by its upstream activator MEK1/2[1].
A cell-permeable and reversible thiazolidinedione compound that displays anti-proliferative properties (IC50 ≤ 25 μM in HeLa, A549, and SUM-159 tumor cells). Preferentially binds to ERK2 with a KD of ~5 μM and prevents its interaction with protein substrates. Shown to block ERK-mediated phosphorylation of ribosomal S6 kinase-1 (RSK-1) and ternary complex factor Elk-1 in HeLa cells, while exhibiting little effect on ERK1/2 phosphorylation by MEK1/2.
[1] Chad N Hancock, et al. Identification of novel extracellular signal-regulated kinase docking domain inhibitors. J Med Chem. 2005 Jul 14;48(14):4586-95. DOI:
10.1021/jm0501174
