Structural analysis of activity-modulating mutations of DUSP19

Abstract

The activity of cellular signaling proteins modulates cellular processes such as cell growth, immune responses, andneuronal development. Dual specificity phosphatases (DUSPs), which constitute a subfamily of protein tyrosinephosphatases (PTPs), are potential targets for therapeutic development. Recently, allosteric inhibitors of PTPs have shownpromising results with regard to their potency, selectivity and membrane permeability. However, detailed understanding ofthe activity regulation of PTPs is limited. Thus, we determined crystal structures of activity-modulating mutants of DUSP19for which strongly-diffracting crystals are available. One allosteric residue (Ile 187) and two active site residues (Ser 150and Arg 156) were mutated to alanine. High-resolution crystal structure determination and enzyme kinetics analysis of thethree mutants revealed that the mutations resulted in rearrangements in allosteric and local structures. In particular, cavityfillingrearrangements in the I187A mutant were conveyed to the active site, leading to allosteric regulation of enzymeactivity.