PFDN1

PFDN1, or prefoldin subunit 1, is a protein encoded by the human PFDN1 gene. It is a component of the prefoldin complex, a molecular chaperone that assists in the correct folding of nascent polypeptides in the cytoplasm. In humans, the prefoldin complex is a heterohexamer comprising six subunits, PFDN1 through PFDN6. The complex forms an elongated, jellyfish-like structure with coiled-coil domains and functions as a cofactor that delivers unfolded substrates to the cytosolic chaperonin CCT/TRiC for productive folding.

Functionally, prefoldin acts co-translationally to capture newly synthesized polypeptides and present them to CCT/TRiC, facilitating folding processes critical for cytoskeletal proteins. The best-established substrates include actin and tubulin, which are essential for cytoskeletal organization and dynamics. By aiding proper folding, PFDN1 and the other subunits contribute to cell viability, morphology, and division, with disruptions in prefoldin function affecting cellular fitness in model systems.

Structure and localization are consistent with its role as a subunit of a cytosolic chaperone complex. PFDN1 contains coiled-coil regions that enable interactions with other prefoldin subunits and with substrate proteins. The protein is predominantly localized in the cytoplasm, where it participates in the early stages of substrate delivery to CCT/TRiC.

Genomically, PFDN1 is conserved across eukaryotes and is broadly expressed in human tissues. While there are studies investigating changes in prefoldin subunit expression in certain cancers and developmental contexts, there are no widely established disease-causing mutations attributed specifically to PFDN1 at this time.

See also: prefoldin, CCT/TRiC chaperonin complex.