PEX14P, A PEROXISOMAL MEMBRANE-PROTEIN BINDING BOTH RECEPTORS OF THE 2 PTS-DEPENDENT IMPORT PATHWAYS

Pex14p, an S. cerevisiae peroxin, is attached to the outer face of the peroxisomal membrane and is a component of the protein import machine ry. Pex14p interacts with both the PTS1 and PTS2 receptors. It is the only known peroxisomal membrane protein that binds the PTS2 receptor a nd might thus mediate the membrane docking event of PTS2-dependent pro tein import. These results suggest that the two import pathways overla p and, furthermore, that Pex14p represents the point of convergence. P ex14p also interacts with two other membrane-bound peroxins including Pex13p, another binding protein for the PTS1 receptor. The data presen ted here are consistent with the idea of a common translocation machin ery for both PTS-dependent protein import pathways in the peroxisomal membrane.