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Updated: May 25, 2026
Analyzing Mitochondrial Function in a Drosophila melanogaster PINK1B9-Null Mutant Using High-resolution Respirometry
Published on: November 10, 2023
Genetic analysis of mitochondrial protein misfolding in Drosophila melanogaster
I Pimenta de Castro1, A C Costa, D Lam
1Cell Death Regulation, MRC Toxicology Unit, Leicester, UK.
Abstract:
Protein misfolding has a key role in several neurological disorders including Parkinson's disease. Although a clear mechanism for such proteinopathic diseases is well established when aggregated proteins accumulate in the cytosol, cell nucleus, endoplasmic reticulum and extracellular space, little is known about the role of protein aggregation in the mitochondria. Here we show that mutations in both human and fly PINK1 result in higher levels of misfolded components of respiratory complexes and increase in markers of the mitochondrial unfolded protein response. Through the development of a genetic model of mitochondrial protein misfolding employing Drosophila melanogaster, we show that the in vivo accumulation of an unfolded protein in mitochondria results in the activation of AMP-activated protein kinase-dependent autophagy and phenocopies of pink1 and parkin mutants. Parkin expression acts to clear mitochondria with enhanced levels of misfolded proteins by promoting their autophagic degradation in vivo, and refractory to Sigma P (ref(2)P), the Drosophila orthologue of mammalian p62, is a critical downstream effector of this quality control pathway. We show that in flies, a pathway involving pink1, parkin and ref(2)P has a role in the maintenance of a viable pool of cellular mitochondria by promoting organellar quality control.
Insights
Mitochondrial protein misfolding, linked to Parkinson's disease, activates cell-cleaning autophagy. Parkin and PINK1 pathways clear damaged mitochondria, maintaining cellular health.
Area of Science:
- Neuroscience
- Cell Biology
- Genetics
Background:
- Protein misfolding is implicated in neurological disorders like Parkinson's disease.
- Mechanisms of protein aggregation are known in various cellular compartments but not in mitochondria.
- Mitochondrial dysfunction is increasingly recognized in neurodegenerative diseases.
Purpose of the Study:
- To investigate the role of protein aggregation within mitochondria in neurological disorders.
- To elucidate the mechanisms of mitochondrial quality control related to protein misfolding.
- To establish a genetic model for studying mitochondrial proteinopathies.
Main Methods:
- Utilized Drosophila melanogaster as a genetic model system.
- Introduced mutations in PINK1 (human and fly) to study mitochondrial protein misfolding.
- Assessed markers of mitochondrial unfolded protein response and autophagy.
- Investigated the function of Parkin and ref(2)P (Drosophila p62) in mitochondrial quality control.
Main Results:
- Mutations in PINK1 lead to increased misfolded respiratory complex components and mitochondrial unfolded protein response markers.
- In vivo accumulation of unfolded proteins in mitochondria triggers AMP-activated protein kinase-dependent autophagy.
- Parkin expression clears mitochondria with misfolded proteins via autophagic degradation.
- Refractory to Sigma P (ref(2)P) is essential for this mitochondrial quality control pathway.
Conclusions:
- Mitochondrial protein misfolding activates a protective autophagy pathway.
- The PINK1-Parkin-ref(2)P pathway is crucial for maintaining mitochondrial quality control.
- This pathway plays a vital role in preventing the accumulation of damaged mitochondria, relevant to Parkinson's disease pathogenesis.
