DUSP28 crystal structure determination and ligand binding site analysis

Abstract

Dual specificity protein phosphatases (DUSPs) belong to the protein tyrosine phosphatases (PTPs) family. DUSPs dephosphorylate both phospho-serine/threonine and phospho-tyrosine of mitogen activated protein kinases (MAPKs) and control important roles in cell growth, regulation signaling. DUSP28, a member of the atypical DUSPs (A-DUSPs), has a 18kDal of molecular weight and phosphatase domain without MAPKs binding domain (MKB). DUSP28 has dephosphorylation activity. So DUSP28 can dephosphorylate MAPK proteins and control cell signaling. Previous studies have shown that DUSP28 is related to pancreatic cancer and liver cancer. However, DUSP28 structure and detailed function have not been known yet. Here, we used X-ray crystallography method to determinate DUSP28 crystal structure at 2.1Å resolution and compared it with other DUSPs family proteins. In addition, we identified that the zinc acts as allosteric inhibitor of DUSP28 by in vitro enzyme assay using Lineweaver-Burk Plot. Through this study, we were able to determinate DUSP28 crystal structure and predict zinc binding site of DUSP28 in three-dimensional structure.