– PFDN4 is a member of the prefoldin beta subunit family. It is one of six subunits of prefoldin, a molecular chaperone complex that binds and stabilizes newly synthesized polypeptides, thereby allowing them to fold correctly. The complex, consisting of two alpha and four beta subunits, forms a double beta barrel assembly with six protruding coiled-coils. PFDN4 binds specifically to cytosolic chaperonin (c-CPN) and transfers target proteins to it. PFDN4 also binds to nascent polypeptide chain and promotes folding in an environment in which there are many competing pathways for nonnative proteins.