Hwang, S., Song, S., Hong, Y.K., Choi, G., Suh, Y.S., Han, S.Y., Lee, M., Park, S.H., Lee, J.H., Lee, S., Bang, S.M., Jeong, Y., Chung, W.J., Lee, I.S., Jeong, G., Chung, J., Cho, K.S. (2013). Drosophila DJ-1 Decreases Neural Sensitivity to Stress by Negatively Regulating Daxx-Like Protein through dFOXO.  PLoS Genet. 9(4): e1003412.

FBrf0221314

Research paper

DJ-1, a Parkinson's disease (PD)-associated gene, has been shown to protect against oxidative stress in Drosophila. However, the molecular mechanism underlying oxidative stress-induced phenotypes, including apoptosis, locomotive defects, and lethality, in DJ-1-deficient flies is not fully understood. Here we showed that Daxx-like protein (DLP), a Drosophila homologue of the mammalian Death domain-associated protein (Daxx), was upregulated under oxidative stress conditions in the loss-of-function mutants of Drosophila DJ-1β, a Drosophila homologue of DJ-1. DLP overexpression induced apoptosis via the c-Jun N-terminal kinase (JNK)/Drosophila forkhead box subgroup O (dFOXO) pathway, whereas loss of DLP increased resistance to oxidative stress and UV irradiation. Moreover, the oxidative stress-induced phenotypes of DJ-1β mutants were dramatically rescued by DLP deficiency, suggesting that enhanced expression of DLP contributes to the DJ-1β mutant phenotypes. Interestingly, we found that dFOXO was required for the increase in DLP expression in DJ-1β mutants and that dFOXO activity was increased in the heads of DJ-1β mutants. In addition, subcellular localization of DLP appeared to be influenced by DJ-1 expression so that cytosolic DLP was increased in DJ-1β mutants. Similarly, in mammalian cells, Daxx translocation from the nucleus to the cytosol was suppressed by overexpressed DJ-1β under oxidative stress conditions; and, furthermore, targeted expression of DJ-1β to mitochondria efficiently inhibited the Daxx translocation. Taken together, our findings demonstrate that DJ-1β protects flies against oxidative stress- and UV-induced apoptosis by regulating the subcellular localization and gene expression of DLP, thus implying that Daxx-induced apoptosis is involved in the pathogenesis of DJ-1-associated PD.

PMC3616925 (PMC) (EuropePMC)