Phosphatidylinositol Glycan N (PIGN)

PIGN encodes a protein that is involved in glycosylphosphatidylinositol (GPI)-anchor biosynthesis. The GPI-anchor is a glycolipid found on many blood cells and serves to anchor proteins to the cell surface. This protein is expressed in the endoplasmic reticulum and transfers phosphoethanolamine (EtNP) to the first mannose of the GPI anchor. Two alternatively spliced variants, which encode an identical isoform, have been reported.PIGN encodes a deduced 931-amino acid protein with 14 predicted transmembrane domains, potential N-linked glycosylation sites, an ER retrieval motif, and a stop-transfer sequence predicted to direct translocation into the ER. PIGN has a hydrophilic N-terminal ER luminal domain that contains motifs conserved in mammalian phosphodiesterases and pyrophosphatases.