DnaJ homolog subfamily B member 1 (DNAJB1)

Interacts with HSP70 and can stimulate its ATPase activity. Stimulates the association between HSC70 and HIP.

Negatively regulates heat shock-induced HSF1 transcriptional activity during the attenuation and recovery period length of the heat shock response (PubMed:9499401). Stimulates ATP hydrolysis and the folding of unfolded proteins mediated by HSPA1A/B (in vitro) (PubMed:24318877).