Pamoic acid disodium is a potent GPR35 agonist with an EC50 value of 79 nM. Pamoic acid disodium induces GPR35 internalization and activates ERK1/2 with EC50 values of 22 nM and 65 nM, respectively. Pamoic acid disodium potently recruits β-arrestin2 to GPR35 and has an antinociceptive effect.

ERK-IN-2 is a potent, highly seletive and orally active ERK2 inhibitor probe with an IC50 value of 1.8 nM. ERK-IN-2 might lead to off-target toxicity and/or off-target activity at dose >10 μM.

AZ6197 (AZ-6197) is a potent, selective, reversible inhibitor of ERK1/2 with IC50 of <0.3 nM (ERK2), inhibits pERK/pRSK with IC50 of 12/62 nM in A375 cells, respectively.

AX15836 is a highly potent and selective ERK5 inhibitor.