How do our cells build their protein interactome?

Chaperones are cellular factors that help in the folding of newly synthesized polypeptides (or clients) and, in some cases, ensure their integration within larger complexes. They often require non-client proteins, or co-chaperones, to help drive specificity to particular target polypeptides or facilitate the nucleotide hydrolysis cycle of some chaperones. The latest findings on the characterization of the PAQosome (Particle for Arrangement of Quaternary structure; formerly known as R2TP/PFDL complex) published recently in Nature Communications help to explain how this particular co-chaperone plays a central role in organizing our proteome into protein complexes and networks. The exploitation by the cell of alternative PAQosomes formed through the differential integration of homologous subunits, in conjunction with the use of several adaptors (specificity factors), provide the conceptual basis for interaction of multiple clients in a structure that is favorable to their simultaneous binding en route to protein complex and network assembly/maturation.