Structure of Cu(I)-bound DJ-1 reveals a biscysteinate metal binding site at the homodimer interface: insights into mutational inactivation of DJ-1 in parkinsonism

The Parkinsonism-associated protein DJ-1 has been suggested to activate the Cu-Zn superoxide dismutase (SOD1) by providing its copper cofactor. The structural and chemical means by which DJ-1 could support this function is unknown. In this study, we characterize the molecular interaction of DJ-1 with Cu(I). Mass spectrometric analysis indicates binding of one Cu(I) ion per DJ-1 homodimer. The crystal structure of DJ-1 bound to Cu(I) confirms metal coordination through a docking accessible biscysteinate site formed by juxtaposed cysteine residues at the homodimer interface. Spectroscopy in crystallo validates the identity and oxidation state of the bound metal. The measured subfemtomolar dissociation constant (Kd = 6.41 × 10(-16) M) of DJ-1 for Cu(I) supports the physiological retention of the metal ion. Our results highlight the requirement of a stable homodimer for copper binding by DJ-1. Parkinsonism-linked mutations that weaken homodimer interactions will compromise this capability

ROS-mediated DJ-1 monomerization modulates intracellular trafficking involving Karyopherin-2

Mutations in DJ-1 are a cause of recessive, early-onset Parkinson's disease (PD). Although oxidative stress and mitochondrial integrity have been implicated in PD, it is largely unknown why neurons degenerate. DJ-1 is involved in oxidative stress-mediated responses and in mitochondrial maintenance; however, its specific function remains vague. Here we show that DJ-1 exhibits neuronal dynamic intracellular trafficking, with dimeric/monomeric cycling modulated by the oxidative environment. We demonstrate that oxidative stress enhances monomerization of wild-type cytosolic DJ-1, leading to nuclear recruitment. The pathogenic DJ-1/E163K variant is unable to homodimerize but is retained in the cytosol upon wild-type DJ-1 heterodimerization. We found that this wild-type/pathogenic heterodimer is disrupted by oxidative stress, leading to DJ-1/E163K mitochondrial translocation. We further demonstrated that endogenously expressed wild-type DJ-1 is imported into neuronal nuclei as a monomer and that nucleo-cytoplasmic transport is oxidative stress mediated. We identified a novel proline-tyrosine nuclear localization signal (PY-NLS) in DJ-1, and we found that nuclear monomeric DJ-1 import is mediated by an oxidative stress-dependent interaction with karyopherin β2. Our study provides evidence that oxidative stress-mediated intracellular trafficking of DJ-1, mediated by dynamic DJ-1 dimeric/monomeric cycling, is implicated in PD pathogenesis