Parkinson’s disease (PD) is a leading cause of neurodegeneration in man. Mutations in the PINK1 kinase lead to autosomal recessive PD. Previous research in our lab has defined a cell signalling pathway for PINK1. Under basal conditions PINK1 is inactive however upon exposure to mitochondrial uncouplers that induce mitochondrial depolarization, PINK1 becomes stabilized and activated. Upon activation PINK1 phosphorylates a Parkinson’s disease-linked ubiquitin ligase, Parkin and ubiquitin. We also showed that PINK1 stimulates phosphorylation of a subset of Rab GTPases at a highly conserved serine residue .
The molecular impact of Rab phosphorylation remains mysterious. The primary aim of the project is to elaborate the effect of phosphorylation on protein-protein interactions using state-of-the-art proteomic technologies from a variety of cellular systems including relevant primary neuronal cell systems. The student will also train in genome-editing technologies to harness the powerful CRISPR/Cas9 methodology to knockout candidate interactors to determine their effect on PINK1-dependent Rab phosphorylation. A major challenge in identifying physiological interactors is their low affinity and the project will collaborate with the Sapkota laboratory that routinely uses proximity labelling mediated by engineering ascorbic acid peroxidase (APEX) technologies to capture the Rab proteome in response to phosphorylation. These studies will lead to greater understanding on how Rabs are regulated that will be of relevance for Parkinson’s disease mechanisms.
- Lai, Y-C., Kondapalli, C., Lehneck, R., Procter J., Dill, B.D., Woodroof, H.I., Gourlay, R., Peggie, M., Campbell, D.G., Itzen, A., Trost, M., Muqit, M.M. (2015) Phospho-proteomic screening identifies Rab GTPases as novel downstream targets of PINK1. The EMBO Journal 34: 2840-61.