Changes in the mitochondrial subproteome of mouse brain Rpn13-binding proteins induced by the neurotoxin MPTP and the neuroprotector isatin

Mitochondrial dysfunction and ubiquitin-proteasome system (UPS) failure contribute significantly to the development of Parkinson's disease (PD). The proteasome subunit Rpn13 located on the regulatory (19S) subparticle play an important role in the delivery of proteins, subjected to degradation, to the proteolytic (20S) part of proteasome. We have previously found several brain mitochondrial proteins specifically bound to Rpn13 (Buneeva et al. (2020) Biochemistry (Moscow), Supplement Series B: Biomedical Chemistry, 14, 297-305). In this study we have investigated the effect of the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and the neuroprotector isatin on the mitochondrial subproteome of Rpn13-binding proteins of the mouse brain. Administration of MPTP (30 mg/kg) to animals caused movement disorders typical of PD, while pretreatment with isatin (100 mg/kg, 30 min before MPTP) reduced their severity. At the same time, the injection of MPTP, isatin, or their combination (isatin + MPTP) had a significant impact on the total number and the composition of Rpn13-binding proteins. The injection of MPTP decreased the total number of Rpn13-binding proteins in comparison with control, and the injection of isatin prior to MPTP or without MPTP caused an essential increase in the number of Rpn13-binding proteins, mainly of the functional group of proteins participating in the protein metabolism regulation, gene expression, and differentiation. Selected biosensor validation confirmed the interaction of Rpn13 subunit of proteasome with some proteins (glyceraldehyde-3-phosphate dehydrogenase, pyruvate kinase, histones H2A and H2B) revealed while proteomic profiling. The results obtained testify that under the conditions of experimental MPTP-induced parkinsonism the neuroprotective effect of isatin may be aimed at the interaction of mitochondria with the components of UPS.