Involved in peroxisome biosynthesis (PubMed:1894692). Acts as a regulator of MSP1 by inhibiting the ability of MSP1 to unfold target proteins (PubMed:32541053). Interacts with MSP1; leading to inhibit the translocase activity of MSP1. By oleic acid. Lack of this protein causes the peroxisomal-deficient phenotype and mislocalization in the cytosol of peroxisomal matrix proteins. Present with 1400 molecules/cell in log phase SD medium. Belongs to the peroxin-3 family.