For example, neddylation of Parkin, a Ub ligase that mediates the selective degradation of damaged mitochondria through a process known as mitophagy (Ni et al., 2014), was shown to increase Parkin Ub ligase activity in neuronal and cancer cells, possibly owing to its enhanced association with Ub E2 enzymes and substrates (Choo et al., 2012; Um et al., 2012). The gene discussed is PRKN; the disease is cancer.