DJ-1 in idiopathic Parkinson's disease

Characteristics of DJ-1 protein in Parkinson’s Disease (PD)

Parkinson‘s Disease • Neurodegenerative disorder • Selective loss of dopamine (DA) neurons in the substantia nigra • Symptoms: resting tremor, rigidity, and slowness of movement. • Traditional treatment includes substituting for the lack of DA, eg with L-Dopa. Problematic • About 1-2% of the population over 65 affected, of these 10% inherited. • 10 different loci have been identified to date whose mutation appears connected to PD eg alpha-synuclein and parkin. • PARK7 locus codes for DJ-1.

DJ-1 • 189 AA protein belonging to the ThiJ/PfpI protease family • homodimer • implicated for example in male fertility, cancer etc. • DJ-1 is widely expressed especially in subcortical regions, in both neurones and astrocytes. • Mostly localises to the cytoplasm, but also to mitochondria, especially in the case of increased oxidative stress. • In the presence of reactive oxygen species (ROS), the isoelectric point (pI) of DJ-1 becomes markedly more acidic. • Sensitive to oxidative stress, mainly through Cysteine 106.

Crystal Structure of DJ-1 Monomers 1+2: green and purple Cys-106: yellow Leu-166: red

Mutations in DJ-1 • Mutations in the DJ-1 gene have been shown to cause early onset recessive autosomal early onset PD • L166P point mutation prevents dimerization of DJ-1. • Other mutations also present, eg early truncation due to wrong insertion of stop codon. • One possible cause for PD might be damage of neurones through inability to deal with the ROS accumulating during the metabolism of DA. • Overexpression of DJ-1 has neuroprotective properties against oxidative stress.

Aims of the project • Aim is to further characterise DJ-1 and to examine putative differences between distribution and biochemistry of DJ-1 between PD and healthy brains, • Investigate DJ-1’s neuroprotective effects in the healthy and mutated state. • The project will be based on ongoing studies in the Bandopadyhay lab. STUDYING THE BIOCHEMICAL NATURE OF DJ-1 IN HUMAN BRAIN - Comparison of insoluble and soluble DJ-1 in different regions of the brain, eg cerebellum, cortex, striatum, substantia nigra of healthy and PD brains, as well as sub-cellular localisation, using 2D gel electrophoresis. - In 2D gel electrophoresis proteins are separated according to molecular weight (size) and pI.

IMMUNOHISTOCHEMISTRY - DJ-1 also present in glial inclusions in multiple system atrophy. - But to date it could not be shown that DJ-1 stains Lewy bodies, inclusions abundant in PD. - Labelling brain slices of various regions, investigate whether DJ-1 can be localised to Lewy bodies after all. - Use antibody against DJ-1, make that antibody visible with dyes. - Attempt to co-immunoprecipitate DJ-1 and alpha-synuclein.

Example of Immunohistochemistry

CELL CULTURE WORK • Using various toxins on cell culture in different concentrations. Eg: rotenone or paraquat • Investigate how those toxins affect the sub- cellular localisation of DJ-1. • Also see how mitochondria are affected by assaying citrate synthase activity.

References • Bandopadhyay et al (2003). The expression of DJ-1 (PARK7) in normal human CNS and idiopathic Parkinson’s disease. Brain 127: 420-430. • Bonifati et al (2004). Linking DJ-1 to neurodegeneration offers novel insights for understanding the pathogenesis of Parkinson’s Disease. J. Mol. Med. 82: 163-174. • Canet-Avilés et al (2004). The Parkinson's disease protein DJ-1 is neuroprotective due to cysteine-sulfinic acid-driven mitochondrial localization. PNAS 101: 9103-9108. • Choi et al (2006). Oxidative Damage of DJ-1 is linked to sporadic Parkinson and Alzheimer Diseases. J. Bio. Chem. 281: 10816-10824. • Cookson (2005) The Biochemistry of Parkinson’s disease. Annu. Rev. Biochem 74: 24-52. • Moore et al (2005). Molecular Pathophysiology of Parkinson’s Disease. Annu. Rev. Neurosci. 28: 57-87. • Wilson et al (2003). The 1.1A resolution crystal structure of DJ-1, the protein mutated in autosomal recessive early onset Parkinson’s disease. PNAS 100: 9256-9261. • Wood-Kaczmar et al (2006). Understanding the molecular causes of Parkinson’s Disease. Trends in Mol. Med. 388.

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DJ-1 in idiopathic Parkinson's disease

by Laura Kilarski on Jul 13, 2009

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DJ-1 in idiopathic Parkinson’s disease — Presentation Transcript