The peroxisomal targeting signal type1 (PTS1) receptor, PEX5, is one member of peroxins (PEXs) which are proteins required for peroxisome assembly. PEX5 and PEX7 function as receptors that recognize PTS1- and PTS2- containing proteins, respectively, and PEX5 binds PTS1 through its C-terminal 40-kDa tetratricopeptide repeat domain. It is a predominantly cytoplasmic, partly peroxisomal protein that appears to shuttle between these compartments as it mediates the import of PTS1-containing proteins. PEX5 has been reported to interact with PEX10, PEX12, PEX13, and PEX14. Defects in PEX5 are a cause of Zellweger syndrome (ZWS), which is a lethal peroxisome biogenesis disorder. This antibody recognizes endogenous PEX5, which migrates with an apparent molecular mass of 80 kDa (PMID: 7790377).