Phosphatidylinositol Glycan S (PIGS)

PIGS encodes a protein that is involved in GPI-anchor biosynthesis. The glycosylphosphatidylinositol (GPI) anchor is a glycolipid found on many blood cells and serves to anchor proteins to the cell surface. This gene encodes an essential component of the multisubunit enzyme, GPI transamidase. GPI transamidase mediates GPI anchoring in the endoplasmic reticulum, by catalyzing the transfer of fully assembled GPI units to proteins.Pigs is not required for GPI synthesis but is essential for attachment of GPI to proteins. During the GPI attachment process, GPI transamidase forms a carbonyl intermediate with the precursor protein, and in the absence of Pigs, the carbonyl intermediate was not generated. The lack of Pigs did not affect the expression of the other GPI transaminase subunits Gaa1 (GPAA1), Gpi8 (PIGK), or Pigt.