a co-chaperone for HSP70 and HSC70 chaperone proteins. Acts as a nucleotide-exchange factor (NEF) promoting the release of ADP from the HSP70 and HSC70 proteins thereby triggering client/substrate protein release. Nucleotide release is mediated via its binding to the nucleotide-binding domain (NBD) of HSC70 where as the substrate release is mediated via its binding to the substrate-binding domain (SBD) of HSC70. Has anti-apoptotic activity. Plays a role in the HSF1 nucleocytoplasmic transport. May be involved in neuronal differentiation and migration. Note: This description may include information from UniProtKB.