Protein Hikeshi (C11orf73) is a nuclear import carrier protein for heat-shock 70 proteins (HSP70s) in response to heat-shock stress. It is only able to bind HSP70s when they are bound to ATP. DnaJ homolog subfamily members (aka heat-shock 40 proteins, HSP40s) also translocate to the nucleus under heat-shock stress (Hattori et al. 1992) and can act as stimulators of intrinsic ATPase activity of HSP70s. The result is that Hikeshi dissociates from HSP70:ADP.
ATPase activator activity of DNAJB1,B6,C2,C7 [nucleoplasm]