Pex16

Pex16, also known as PEX16, is a peroxisomal membrane protein that is essential for peroxisome biogenesis. It is conserved across eukaryotes, including yeast, plants, and animals, and belongs to the family of peroxins (PEX proteins) that coordinate peroxisome assembly and maintenance.

Localization and structure: In most organisms, PEX16 is an integral membrane protein of the peroxisomal membrane, typically containing multiple transmembrane segments. It functions early in peroxisome formation and is thought to act as a docking factor for other peroxins, such as PEX3 and PEX19, to promote the proper targeting and insertion of additional peroxisomal membrane proteins.

Function: PEX16 contributes to the formation of peroxisomal membranes and the correct assembly of the peroxisomal protein import machinery. Through interactions with PEX3 and PEX19, it helps recruit and organize other peroxisomal membrane proteins, supporting the biogenesis and maintenance of functional peroxisomes. It also participates in the trafficking of matrix proteins via the peroxisomal import machinery.

Genetic and clinical significance: Mutations in PEX16 can cause peroxisome biogenesis disorders, a spectrum that includes Zellweger spectrum disorders. Clinical presentation varies from severe congenital forms to milder phenotypes and typically features defects in peroxisomal metabolism, such as abnormal very-long-chain fatty acid levels and reduced plasmalogens. Diagnosis is based on genetic testing and biochemical markers of peroxisome function.

Research context: PEX16 has been studied in yeast and vertebrate systems using gene knockout or knockdown approaches. Loss or alteration of PEX16 disrupts peroxisome formation and membrane protein targeting, underscoring its essential role in the early steps of peroxisome biogenesis.