Inactivates MAPK1 and MAPK3 which leads to dephosphorylation of heat shock factor protein 4 and a reduction in its DNA-binding activity. Inhibits MAP kinase p38 by dephosphorylating it and inhibits p38-mediated apoptosis in anaplastic thyroid cancer cells. Can also induce activation of MAP kinase p38 and c-Jun N-terminal kinase (JNK).
Tissue specificity:Brain. In the brain it is expressed ubiquitously except in the hippocampus. Expressed in embryonal cancers (retinoblastoma, neuroepithilioma and neuroblastoma) and in anaplatic thyroid cancer.