Import receptor for peroxisomal-targeting signal one (PTS1). A receptor-cargo complex composed of PEX5, PEX7, a PTS1-containing protein and a PTS2-containing protein is targeted to peroxisomes during import. Necessary for the developmental elimination of obsolete peroxisome matrix proteins. Interacts (via N-terminus) with PEX7 (via C-terminus), (via WXXXF/Y repeats) with PEX14 and (via TPR repeats) with PTS1-containing proteins. Interacts with LACS7. Expressed in flowers, siliques, leaves and roots. Expressed at the early stage of germination and during the conversion of glyoxysomes to peroxisomes. Accumulates at high levels in seedlings and at lower levels as plants mature. Up-regulated by hydrogen peroxide, the absence of sucrose and by dark versus light conditions. May be monoubiquitinated by PEX4 and PEX12 for recycling from the peroxisome. Peroxisome-defective phenotype including an absolute requirement for sucrose during early development, high seedling lethality, and delayed development. PEX5 stability in light-grown seedlings depends on PEX7. Belongs to the peroxisomal targeting signal receptor family.