Some proteins need to interact with various polypeptides to attain correct folded shapes. These helper peptides are called molecular chaperones. Molecular chaperones comprise a great variety of proteins that are essential for protein binding and translocation across cellular compaments, assembling multi-protein complexes, preventing aggregation, and directing mis-folded and sho-lived proteins to degradation by the proteosome. Ref: Harper's Biochemistry 26th Edition, Pages 507-508 ; Molecular Chaperones by Reginald John Ellis, R. A. Laskey, George H. Lorimer, 1993