PION is an alias for the gene, Gamma-secretase activating protein, in humans. Other names include: Gamma-secretase-activating protein; Protein pigeon homolog. The encoded protein has an amino acid length of 854 and a mass of 97.8 kDa. Other isoforms may exist. PION is a member of the GSAP family. This gene shares homology with other species, including: Mouse, Rat, Zebrafish.