DnaJ Homolog Subfamily B Member 1 (DNAJB1) is a member of the heat shock protein family. Heat shock proteins (HSPs) are a highly conserved family of stress response proteins. HSPs function primarily as molecular chaperones, facilitating the folding of other cellular proteins, preventing protein aggregation, or targeting improperly folded proteins to specific degradative pathways. DNAJB1 regulates cellular processes by aiding in the folding, transport and assembly. DNAJB1 contains a J-domain which controls interaction with the ATPase domain of DnaK. DNAJB1 interacts with HSP70 and can stimulate its ATPase activity. In addition, DNAJB1 stimulates the association between HSC70 and HIP.