Mitochondrial localization of the Parkinson's disease related protein DJ-1: implications for pathogenesis

Hum Mol Genet. 2005 Jul 15;14(14):2063-73. doi: 10.1093/hmg/ddi211. Epub 2005 Jun 8.

Abstract

Both homozygous (L166P, M26I, deletion) and heterozygous mutations (D149A, A104T) in the DJ-1 gene have been identified in Parkinson's disease (PD) patients. The biochemical function and subcellular localization of DJ-1 protein have not been clarified. To date the localization of DJ-1 protein has largely been described in studies over-expressing tagged DJ-1 protein in vitro. It is not known whether the subcellular localization of over-expressed DJ-1 protein is identical to that of endogenously expressed DJ-1 protein both in vitro and in vivo. To clarify the subcellular localization and function of DJ-1, we generated three highly specific antibodies to DJ-1 protein and investigated the subcellular localization of endogenous DJ-1 protein in both mouse brain tissues and human neuroblastoma cells. We have found that DJ-1 is widely distributed and is highly expressed in the brain. By cell fractionation and immunogold electron microscopy, we have identified an endogenous pool of DJ-1 in mitochondrial matrix and inter-membrane space. To further investigate whether pathogenic mutations might prevent the distribution of DJ-1 to mitochondria, we generated human neuroblastoma cells stably transfected with wild-type (WT) or mutant (M26I, L166P, A104T, D149A) DJ-1 and performed mitochondrial fractionation and confocal co-localization imaging studies. When compared with WT and other mutants, L166P mutant exhibits largely reduced protein level. However, the pathogenic mutations do not alter the distribution of DJ-1 to mitochondria. Thus, DJ-1 is an integral mitochondrial protein that may have important functions in regulating mitochondrial physiology. Our findings of DJ-1's mitochondrial localization may have important implications for understanding the pathogenesis of PD.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Blotting, Western
  • Cell Nucleus / metabolism
  • Electrophoresis, Polyacrylamide Gel
  • Heterozygote
  • Humans
  • Immunohistochemistry
  • Intracellular Signaling Peptides and Proteins
  • Microscopy, Electron
  • Mitochondria / metabolism
  • Mutation
  • Oncogene Proteins / genetics
  • Oncogene Proteins / metabolism*
  • Parkinson Disease / metabolism*
  • Protein Deglycase DJ-1
  • Subcellular Fractions / metabolism

Substances

  • Intracellular Signaling Peptides and Proteins
  • Oncogene Proteins
  • PARK7 protein, human
  • Protein Deglycase DJ-1