PFDN1 is one of sixsubunits of prefoldin, a heterohexameric chaperone protein which assists in the correct folding of other proteins. This protein delivers nonnative target proteins, principally actins and tubulins, to the eukaryotic cytosolic chaperonin for facilitated folding. Defects in PFDN1 displayed phenotypes characteristic of defects in cytoskeletal function, including manifestations of ciliary dyskinesia, neuronal loss, and defects in B and T cell development and function.