One HIP oligomer binds the ATPase domains of at least two HSC70 molecules dependent on activation of the HSC70 ATPase by HSP40. Stabilizes the ADP state of HSC70 that has a high affinity for substrate protein. Through its own chaperone activity, it may contribute to the interaction of HSC70 with various target proteins. Homotetramer. Interacts with HSC70 as well as DNAJ homologs and HSP90. Interacts (via the C-terminus 303- 319 AA) with GRK5. Belongs to the FAM10 family. Note: This description may include information from UniProtKB.