May dephosphorylate MAPK13, ATF2, ERBB3, PDGFRB and SNX6 (PubMed:22792334). May play a role in the regulation of oligodendrocyte differentiation. May play a role in the regulation of myelin formation (By similarity). Involved in the regulation of Erk1/2 phosphorylation in Schwann cells; the signaling may be linked to the regulation of myelination (By similarity). H2O + O-phospho-L-tyrosyl-[protein] = L-tyrosyl-[protein] + phosphate H2O + O-phospho-L-seryl-[protein] = L-seryl-[protein] + phosphate H2O + O-phospho-L-threonyl-[protein] = L-threonyl-[protein] + phosphate Highly expressed in testis (PubMed:15138252). Expressed in brain; up-regulated in patients with multiple sclerosis gray matter lesions (PubMed:22792334). Belongs to the protein-tyrosine phosphatase family. Non-receptor class dual specificity subfamily. Although assigned as two separate genes (c20orf57 and DUSP15), it is probable that C20orf57 does not exist by itself and is a part of the DUSP15 gene.