Claim: DUSP1 suppresses the activation of MAP kinase, Mitogen-activated protein kinase 1 for example, and specifies a protein with structural features similar to members of the non-receptor-type protein-tyrosine phosphorylases family.
Evidence: Furthermore, it suppresses the activation of MAP kinase by oncogenic ras in extracts of Xenopus oocytes. The bacterially expressed and purified DUSP1 protein has intrinsic phosphatase activity, and specifically inactivates mitogen-activated protein (MAP) kinase in vitro by the concomitant dephosphorylation of both its phosphothreonine and phosphotyrosine residues. It specifies a protein with structural features similar to members of the non-receptor-type protein-tyrosine phosphatase family, and which has significant amino-acid sequence similarity to a Tyr/Ser-protein phosphatase encoded by the late gene H1 of vaccinia virus.