PEX1 is a component of the PEX1-PEX6 AAA ATPase complex, a protein dislocase that mediates the ATP-dependent extraction of the PEX5 receptor from peroxisomal membranes. This is an essential step for PEX5 recycling. The complex specifically recognises PEX5 monoubiquitinated at Cys-11 and pulls it out of the peroxisome lumen through the PEX2-PEX10-PEX12 retrotranslocation channel. Extraction is accompanied by unfolding of the TPR repeats of PEX5 and release of its bound cargo.

The PEX1 gene encodes a member of the AAA ATPase family, a large group of ATPases associated with diverse cellular activities. HGNC places it in the AAA ATPases and Peroxins gene groups. The PEX1 protein is cytoplasmic but is often anchored to a peroxisomal membrane, where it forms a heteromeric complex and contributes to the import of proteins into peroxisomes and to peroxisome biogenesis. Alternatively spliced transcript variants have been reported for the gene.

The aliases ZWS1 and ZWS, and the previous names Zellweger syndrome 1 and Zellweger syndrome, reflect the disease association of the locus. Mutations in the PEX1 gene have been associated with complementation group 1 peroxisomal disorders, including neonatal adrenoleukodystrophy, infantile Refsum disease and Zellweger syndrome. The mouse ortholog is Pex1 and the rat ortholog is listed as Znf260.