Mitophagy & mitochondrial quality control in disease

RESEARCH BACKGROUND Parkinson’s disease (PD) is one of the most common of the neurodegenerative disorders, affecting 1-2% of the population worldwide. Multiple lines of evidence place mitochondrial dysfunction as a central player in the pathogenesis of PD. Two proteins commonly mutated in familial PD, PINK1 and Parkin, play a key role in maintaining mitochondrial health by identifying damaged mitochondria and degrading them through a selective form of autophagy termed mitophagy (Lazarou et al., (2015) Nature). Our lab investigates the molecular mechanisms of PINK1/Parkin mitophagy. We are interested in how PINK1 and Parkin drive the sequestration of damaged mitochondria within double membrane structures called autophagosomes, before delivering them to lysosomes for degradation. The PINK1/Parkin mitophagy projects on offer provide experience with a variety of biochemical and cell biological techniques including state-of-the-art confocal microscopy, the latest generation of genome engineering technology (CRISPR/Cas9), tissue culture, western blotting, stable protein expression using retrovirus, molecular biology and mass spectrometry. These techniques enable students to gain experience in a range of scientific approaches and provide students with a strong scientific foundation to build on. HONOURS PROJECTS Project 1: Characterisation of novel PINK1/Parkin mitophagy factors Using quantitative proteomics of autophagy defective cell lines, we have identified a number of novel PINK1/Parkin mitophagy candidate proteins. Some of these proteins have predicted functions in vesicle trafficking and membrane fusion, while others have no known function. This project will utilise CRISPR/Cas9 gene editing to generate knockout cell lines of the putative novel mitophagy factors in order to determine whether the factors are required for PINK1/Parkin mitophagy. Furthermore, how the factors regulate the molecular signals that govern the clearance of defective mitochondria will be investigated. For example; are they required for autophagosome formation, or for the recognition of damaged mitochondria? Project 2: Investigating the interplay of PINK1/Parkin mitophagy and the mitochondrial unfolded protein response (mtUPR) In addition to PINK1/Parkin mitophagy, mitochondria also repair damage by activating the mtUPR. The mtUPR clears the build up of misfolded protein aggregates in mitochondria by inducing various chaperones, proteases and cytoprotective factors. However, how PINK1/Parkin mitophagy and the mtUPR work together is unknown despite the fact that both pathways are activated in response to mitochondrial damage. This project will use cell lines lacking PINK1/Parkin mitophagy and/or the mtUPR to 1) understand how the mtUPR and PINK1/Parkin mitophagy work together to maintain healthy mitochondria, and 2) to identify and characterise new molecular factors that link the two pathways. Understanding how the pathways cooperate will identify targets that promote mitochondrial health and potentially help prevent mitochondrial dysfunction in Parkinson’s disease.