DJ-1 protects proteins from acylation by catalyzing the hydrolysis of highly reactive cyclic 3-phosphoglyceric anhydride.

Abstract

Mutations in the human PARK7 gene that encodes protein DJ-1 lead to familial Parkinsonism due to loss of dopaminergic neurons. However, the molecular function of DJ-1 underpinning its cytoprotective effects are unclear. Recently, DJ-1 has been shown to prevent acylation of amino groups of proteins and metabolites by 1,3-bisphosphoglycerate. This acylation is indirect and thought to proceed via the formation of an unstable intermediate, presumably a cyclic 3-phosphoglyceric anhydride (cPGA). Several lines of evidence indicate that DJ-1 destroys cPGA, however this enzymatic activity has not been directly demonstrated. Here, we report simple and effective procedures for synthesis and quantitation of cPGA and present a comprehensive characterization of this highly reactive acylating electrophile. We demonstrate that DJ-1 is an efficient cPGA hydrolase with k_cat/K_m = 5.9 × 10⁶ M^-1s^-1. Experiments with DJ-1-null cells reveal that DJ-1 protects against accumulation of 3-phosphoglyceroyl-lysine residues in proteins. Our results establish a definitive cytoprotective function for DJ-1 that uses catalytic hydrolysis of cPGA to mitigate the damage from this glycolytic byproduct.