Pex14

Pex14, or peroxin 14, is a peroxisomal membrane protein that participates in the import of matrix proteins into peroxisomes. It localizes to the outer membrane of peroxisomes, where it contributes to the docking and translocation of cargo-bearing receptors.

In most organisms, Pex14 forms a docking interface with other peroxins such as Pex13 and Pex17 (in yeast) or PEX13 (in animals). It docks the cytosolic receptor PEX5 when it carries peroxisomal targeting signal type 1 (PTS1) proteins. PEX5 then facilitates the translocation of these proteins into the peroxisomal matrix, with assistance from the rest of the import machinery.

With regard to structure, Pex14 is an integral membrane protein containing a transmembrane region that anchors it to the peroxisomal membrane and a cytosolic N-terminal domain that binds PEX5. The precise topology and interaction details are conserved across species, though the composition of the docking complex varies (for instance, Pex17 is present in yeast but not in all animals).

Pex14 is broadly conserved among eukaryotes, including fungi and metazoans. Disruption of Pex14 function can impair peroxisomal protein import and contribute to peroxisome biogenesis disorders, such as Zellweger spectrum disorders, though pathogenic variants of PEX14 are relatively uncommon compared with other peroxin defects.