Molecular chaperones are key players in proteostasis, the balance between 
protein synthesis, folding, assembly and degradation. They are helped by a 
plethora of cofactors termed cochaperones, which direct chaperones towards any 
of these different, sometime opposite pathways. One of these is prefoldin (PFD), 
present in eukaryotes and in archaea, a heterohexamer whose best known role is 
the assistance to group II chaperonins (the Hsp60 chaperones found in archaea 
and the eukaryotic cytosolic) in the folding of proteins in the cytosol, in 
particular cytoskeletal proteins. However, over the last years it has become 
evident a more complex role for this cochaperone, as it can adopt different 
oligomeric structures, form complexes with other proteins and be involved in 
many other processes, both in the cytosol and in the nucleus, different from 
folding. This review intends to describe the structure and the many functions of 
this interesting macromolecular complex.