PEX5

The protein encoded by PEX5 is peroxisomal biogenesis factor 5, commonly referred to as the PTS1 receptor. It acts as a critical mediator of peroxisomal protein import: it recognizes and binds to proteins carrying the peroxisomal targeting signal 1 (PTS1) at their C-terminus, then shuttles these proteins into peroxisomes, supporting peroxisome biogenesis and lipid metabolic processes.
Mutations in PEX5 lead to Zellweger syndrome spectrum (ZSS) disorders, a set of peroxisomal biogenesis defects marked by neurodevelopmental delays, hepatic impairment, and retinal abnormalities. Current treatments are supportive, but preclinical research focuses on gene therapy—such as AAV vector-mediated delivery of functional PEX5—to restore peroxisomal function in affected individuals.