In this aspect nutraceuticals could serve useful to protect against further insult to an already vulnerable proteosomal complex, not only due to mutations in parkin, but also due to lack of endogenous proteasome activator PA28 expression in the SNc, concomitant to reduced function of α-subunit of the 20S proteasome in the SNc of sporadic PD patients [543,544]. Here, PRKN is linked to Parkinson disease.