This gene encodes an endoplasmic reticulum associated protein that is involved in glycosylphosphatidylinositol (GPI)-anchor biosynthesis. The GPI anchor is a glycolipid found on many blood cells and which serves to anchor proteins to the cell surface. The protein encoded by this gene is a subunit of the GPI N-acetylglucosaminyl (GlcNAc) transferase that transfers GlcNAc to phosphatidylinositol (PI) on the cytoplasmic side of the endoplasmic reticulum. [provided by RefSeq, Jul 2008].