Plays an important role in cell protection against oxidative stress and cell death by acting as a oxidative stress sensor (PubMed:16139214, PubMed:16203113, PubMed:16894167, PubMed:20457924). Does not play a role in methylglyoxal detoxification (PubMed:27903648). Plays a role in mitochondrial function together with Pink1 (PubMed:20457924). In motor neurons regulates structural synaptic plasticity of locomotor behavior as part of the PTEN-phosphatidylinositol 3-kinase pathway in response to oxygen species (ROS) levels (PubMed:30540251). Expressed in the head and testis (at protein level) (PubMed:16139213). Ubiquitously expressed at constant levels (PubMed:16139214). Detected during embryogenesis (at protein level) (PubMed:16139213). Maternally contributed, after which its levels fall slightly in embryo but increase again through development and in adult (PubMed:16139214, PubMed:16203113). Oxidation of Cys-45 and Cys-104 in response to oxidative stress (PubMed:16894167, PubMed:22515803). Levels of oxidation increase with age (PubMed:16894167). Viable and fertile (PubMed:16203113). Larvae develop normally but show increased oxidative stress-induced cell death (PubMed:23593018, PubMed:30540251). Larvae show structurally normal neuromuscular junctions, however they fail to show structural synaptic plasticity in response to oxygen species (ROS) levels (PubMed:30540251). Adult flies show severe defects in locomotor ability without loss of dopaminergic neurons and increased sensitivity to oxidative stress (PubMed:16139214, PubMed:16203113, PubMed:23593018). Results in altered subcellular localization of Daxx (PubMed:23593018). Does not show more elevated levels of methylglyoxal adducts than controls (PubMed:27903648). Double knockouts for dj-1beta and dj-1alpha is viable but with reduced male fertility (PubMed:16139213, PubMed:20457924). Double knockouts for dj-1beta and dj-1alpha is more sensitive to chemical agents that induce oxidative stress (PubMed:16139213). Double knockouts for dj-1beta and dj-1alpha shows reduced lifespan and decreased spontaneous movement over time (PubMed:20457924). Double knockouts for dj-1beta and dj-1alpha spermatozoa are morphologically normal but immotile with abnormal vacuoles in the Nebenkern, abnormal mitochondria and aberrant separation of investment cones during sperm individualization (PubMed:20457924). Double knockouts for DJ-1beta and Daxx restore normal number of dopaminergic neurons, locomotor activity and sensitivity to oxidative stress and UV-induced damage (PubMed:23593018).