VHR: ProductsVaccinia Virus VH1-related Phosphatase (VHR), also known as Dual-Specificity Phosphatase 3 (DUSP3), removes phosphate groups from tyrosine, serine, and threonine residues. It belongs to a family of phosphatases that selectively dephosphorylate MAP kinases. VHR has been shown to act as a phosphatase on several members of the MAP kinase family, including ERK1, ERK2, and JNK. It is a target for the ZAP-70 kinase, and phosphorylation of VHR at tyrosine 138 leads to a downregulation of ERK2 activity. Its well-defined biochemistry has made VHR useful in screening assays for compounds that inhibit phosphatases.