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 kcat/Km = 5.9 × 106 M−1
s−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.
