DUSP26 inactivates MAPK1 and MAPK3 which leads to dephosphorylation of heat shock factor protein 4 and a reduction in its DNA-binding activity. This protein inhibits MAP kinase p38 by dephosphorylating it and inhibits p38-mediated apoptosis in anaplastic thyroid cancer cells. DUSP26 can also induce activation of MAP kinase p38 and c-Jun N-terminal kinase (JNK). Recombinant human DUSP26 protein, fused to His-tag at N-terminus, was expressed in E.coli .