Tanzisertib HCl(CC-930, JNK-930, JNKI-1) is kinetically competitive with ATP in the JNK-dependent phosphorylation of the protein substrate c-Jun and potent against all isoforms of JNK (Ki(JNK1) = 44 ± 3 nM, IC50(JNK1) = 61 nM, Ki(JNK2) = 6.2 ± 0.6 nM, IC50(JNK2) = 5 nM, IC50(JNK3) = 5 nM) and selective against MAP kinases ERK1 and p38a with IC50 of 0.48 and 3.4 μM respectively.