Structural analysis of activity-modulating mutations of DUSP19

The activity of cellular signaling proteins modulates cellular processes such as cell growth, immune responses, and neuronal development. Dual specificity phosphatases (DUSPs), which constitute a subfamily of protein tyrosine phosphatases (PTPs), are potential targets for therapeutic development. Recently, allosteric inhibitors of PTPs have shown promising results with regard to their potency, selectivity and membrane permeability. However, detailed understanding of the activity regulation of PTPs is limited. Thus, we determined crystal structures of activity-modulating mutants of DUSP19 for which strongly-diffracting crystals are available. One allosteric residue (Ile 187) and two active site residues (Ser 150 and Arg 156) were mutated to alanine. High-resolution crystal structure determination and enzyme kinetics analysis of the three mutants revealed that the mutations resulted in rearrangements in allosteric and local structures. In particular, cavityfilling rearrangements in the I187A mutant were conveyed to the active site, leading to allosteric regulation of enzyme activity.