Figure 11.

Working Model of Peroxisomal Protein Import.

DAU/APEM9 is transported to the peroxisomal membrane by PEX19, probably via a similar mechanism as PEX16 and PEX10 (Hu et al., 2012). DAU/APEM9 regulates PTS1- and PTS2-containing peroxisomal matrix protein import via PEX14, which interacts directly with the PTS1 receptor PEX5 and another membrane protein PEX13, which binds to the PTS2 receptor PEX7. The docked receptor-cargo complex translocates the cargo PTS1- and PTS2-containing protein into the peroxisome matrix, and the receptors are recycled back to the cytosol in aid of the RING-finger proteins PEX2, PEX10, and PEX12 and the AAA-ATPase PEX1-PEX6. DAU/APEM9 tethers the PEX1-PEX6 complex to the peroxisomal membrane.