Plays an indispensable role in the organization of KRT8/KRT18 filaments. Acts as an endogenous molecular chaperone for neuronal proteins including huntingtin. Suppresses aggregation and toxicity of polyglutamine-containing, aggregation-prone proteins (By similarity). 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. Also reduces cellular toxicity and caspase-3 activity (By similarity). Homooligomer. Interacts with BAG3, HSPB8 and STUB1. Interacts with HSP70, KRT18 and PTTG. Interacts with ALKBH1. Highest levels of expression found in brain and retina, and lower levels in heart, kidney, liver and placenta. Low levels detected in testes at day 7 postnatally, with 10-fold increased levels detected by day 28, remaining into adulthood.