Involved in peroxisome biosynthesis and integrity. Assembles membrane vesicles before the matrix proteins are translocated. As a docking factor for PEX19, is necessary for the import of peroxisomal membrane proteins in the peroxisomes. {ECO:0000269|PubMed:10848631, ECO:0000269|PubMed:15007061}. This is the function of ENSG00000034693 (PEX3, peroxisomal biogenesis factor 3).