Phosphatidylinositol Glycan H (PIGH)

The PIGH gene encodes an enzyme involved in the biosynthesis of glycosylphosphatidylinositol anchor; see PIGA) and PIGF for other components of the system.Kamitani et al. (1993) isolated cDNA for a human gene that repaired the defect in a complementation class H mutant cell line. They determined that PIGH encodes a predicted protein of 188 amino acids.Watanabe et al. (1996) demonstrated that the PIGA and PIGH proteins form a protein complex and are subunits of the GPI GlcNAc transferase of the endoplasmic reticulum (ER). PIGH is a cytoplasmic ER-associated protein.Using immunoprecipitation experiments, Watanabe et al. (1998) demonstrated that PIGQ associates specifically with PIGA, PIGC, and PIGH and that all 4 proteins form a complex that has GPI-GlcNAc transferase (GPI-GnT) activity in vitro.