Golgi-resident glycosylphosphatidylinositol (GPI)-N-acetylgalactosamine transferase involved in the lipid remodeling steps of GPI-anchor maturation. Lipid remodeling steps consist in the generation of 2 saturated fatty chains at the sn-2 position of GPI-anchors proteins . Required for the initial step of GPI-GalNAc biosynthesis, transfers GalNAc to GPI in the Golgi after fatty acid remodeling by PGAP2 .
Subcellular locations: Golgi apparatus membrane