PRKN and retinal degeneration: PTEN-induced putative kinase 1 (PINK1)/Parkinson protein 2, E3 ubiquitin protein ligase (PARKIN) proteins, crucial for mitophagy, are implicated in AMD and PD.[52] Research by Huang et al found that in a Drosophila model of retinal degeneration, photoreceptors exhibit abnormal mitochondrial morphology and functional abnormalities.