Fig. 1. Mitochondria dysfunction and dopaminergic cell death in PD pathogenesis. Multiple factors, including genetics, aging and environmental toxins, or combinations, have been implicated in the aetiology of PD. Abnormal metabolic function, abnormal morphology, and impaired fission-fusion balance have all been observed in mitochondria in at least some forms of PD. Increased OS can lead to impaired function of the UPS, thereby further affecting cell survival. All these may directly or indirectly affect the mitochondrial function of protein degradation systems, including UPS and ALP, and thereby, cause the death of dopamine neurons.
