Has a stimulatory effect on the ATPase activity of HSP70 in a dose-dependent and time-dependent manner and hence acts as a co-chaperone of HSP70 (PubMed:10954706, PubMed:28233300). Plays an indispensable role in the organization of KRT8/KRT18 filaments (PubMed:10954706). Acts as an endogenous molecular chaperone for neuronal proteins including huntingtin (PubMed:11896048, PubMed:22366786). Suppresses aggregation and toxicity of polyglutamine-containing, aggregation-prone proteins (PubMed:20159555, PubMed:22366786). Also reduces cellular toxicity and caspase-3 activity (PubMed:11896048). ; [Isoform B]: Isoform B but not isoform A inhibits huntingtin aggregation.
