HSPA1A-independent suppression of PARK2 C289G protein aggregation by human small heat shock proteins.

The C289G mutation of the parkin E3-ubiquitin protein ligase (PARK2) is associated with autosomal recessive juvenile onset Parkinson's disease and was found to be associated with protein aggregation. Members of the human small heat shock proteins (HSPBs) have been implicated in protein degradation and prevention of protein aggregation. In this study, we show that of the 10 HSPB members, individual overexpression of HSPB1, HSPB2, HSPB4, and HSPB7 suppresses PARK2 C289G-associated protein aggregation. Intriguingly, the protective actions of these HSPBs are not impaired upon inactivation of the ATP-dependent HSP70 chaperone machines. Depending on the HSPB member the protective actions involve either autophagic or proteasomal degradation pathways.