Mass spectrometry highlights effect of oxidisation on parkin

Mass spectrometry has been used in an investigation into the oxidation of the cysteine-rich regions of parkin.

In a study published in the Molecular Neurodegeneration journal, a team of scientists looked into evidence that suggests oxidative/nitrosative stress compromises parkin-mediated ubiquitination and leads to the formation of Lewy bodies (LBs).

An accumulation of aberrant proteins to form LBs is a hallmark of Parkinson's disease (PD).

The study found that exposure to mitochondrial complex I inhibitor 1-methyl-4-phenlypyridinium (MPP+) leads to significant increases in oxidation (sulfonation) and subsequent aggregation of parkin in SH-SY5Y cells.

Furthermore, mass spectrometry analysis revealed that H2O2 reacted with specific cysteine residues of parkin, resulting in sulfination/sulfonation in regions of the protein similar to those affected by parkin mutations in hereditary forms of PD.

"These findings show that oxidative stress alters parkin E3 ligase activity, leading to dysfunction of the ubiquitin-proteasome system and potentially contributing to LB formation," the publication stated.