PRKN and Alzheimer disease: However, our results suggest that Beclin-1 levels are increased in AD brains, perhaps due to different stages of disease pathology and sample extraction between our studies and those reported by (Pickford et al, 2008), but this increase in Beclin-1 is not associated with interaction with parkin, whose solubility is decreased in AD (Lonskaya et al, 2012c).