ABSTRACT
DJ-1, a product of the DJ-1/PARK7 gene, has been suggested to play various functions involved in transcriptional regulation, protease activity, anti-oxidative stress activity, and regulation of mitochondrial complex I. Such a variety of functions of DJ-1 are supposed to be realized through interactions with different partner proteins. Among the candidates for DJ-1-partner proteins detected in TOF-MAS analyses of the cellular proteins co-immunoprecipitated with DJ-1, we focused here pyrroline-5-carboxylate reductase 1, PYCR1, a final key enzyme for proline biosynthesis. DJ-1 directly bound to PYCR1 in vivo and in vitro. DJ-1 and PYCR1 colocalized in mitochondria, and both were suggested to be involved in regulation of mitochondrial membrane potential, but differently. DJ-1 enhanced the enzymatic activity of PYCR1 in vitro. The cells knocked down for DJ-1 and PYCR1 showed lower viability under oxidative stress conditions. No additive nor synergistic results were obtained for the cells that had been knocked down for both DJ-1 and PYCR1, suggesting that DJ-1 and PYCR1 are on the same pathway of anti-oxidative stress protection of the cells.
Subject(s)
Intracellular Signaling Peptides and Proteins/metabolism , Oncogene Proteins/metabolism , Oxidative Stress , Pyrroline Carboxylate Reductases/metabolism , Animals , Blotting, Western , Cell Survival/drug effects , Cell Survival/genetics , Dose-Response Relationship, Drug , Fluorescent Antibody Technique, Indirect , HEK293 Cells , HeLa Cells , Humans , Hydrogen Peroxide/pharmacology , Intracellular Signaling Peptides and Proteins/genetics , Mice , Mice, Knockout , Mitochondria/metabolism , Oncogene Proteins/genetics , Oxidants/pharmacology , Peroxiredoxins , Proline Oxidase/genetics , Proline Oxidase/metabolism , Protein Binding/drug effects , Protein Deglycase DJ-1 , Pyrroline Carboxylate Reductases/genetics , RNA Interference , Signal Transduction/drug effects , delta-1-Pyrroline-5-Carboxylate ReductaseABSTRACT
DJ-1 has recently been shown to be responsible for onset of familial Parkinson's disease (PD), PARK7. DJ-1 has been shown to play roles in transcriptional regulation and anti-oxidative stress, and loss of its function is thought to trigger onset of PD. In this study, a recombinant DJ-1 protein was administrated into the brain of PD model rats that had been injected to 6-hydroxydopamine (6-OHDA) in the left substantia nigra. PD phenotypes, including dopaminergic neuron death in the substantia nigra, decrease in dopamine, and dopamine transporter levels in the striatum, and motor abnormality, were dramatically improved by wild-type DJ-1 but not L166P DJ-1, a mutant form of DJ-1 found in PD patients. Furthermore, production of reactive oxygen species and cell death induced by 6-OHDA in SH-SY5Y cells and mesencephalic neurons were inhibited by addition of the recombinant DJ-1. These findings suggest that DJ-1 is a therapeutic target for PD.
