PINK1 and Parkinson disease: As to PINK1, its direct role in regulating cellular, and most specifically mitochondrial Ca2+ fluxes, has been recently proposed starting with the observation that the co-expression of mutant PINK1 in a cellular model of PD-expressing mutated α-synuclein exacerbated the observed mitochondrial defects, that is, increased mitochondrial size with loss of cristae and reduced ATP levels (Marongiu et al., 2009).