phosphatidylinositol N-acetylglucosaminyltransferase subunit A; GlcNAc-PI synthesis protein; phosphatidylinositol-glycan biosynthesis class A protein; PIG-A (PIGA)

Function

• synthesis of N-acetylglucosaminyl-phosphatidylinositol, very early intermediate in GPI-anchor biosynthesis
• glycolipid biosynthesis: GPI-anchor biosynthesis
• associates with PIGC, PIGH, PIGP, PIGQ & DPM2
• interacts directly with PIGY

Structure

• belongs to the glycosyltransferase 1 family

Compartment

• endoplasmic reticulum membrane
• single-pass membrane protein

Alternative splicing

named isoforms=2

Pathology

• defects in PIGA are the cause of paroxysmal nocturnal hemoglobinuria
• biosynthesis of the GPI anchor is deficient in patients with PNH leading to deficient surface expression of GPI-anchored proteins such as DAF or CD59 which play roles in protection of erythrocytes from hemolysis by complement

More general terms

• phosphatidylinositol-glycan biosynthesis protein (PIG-protein)
• membrane protein
• phosphoprotein
• protein subunit

Additional terms

• paroxysmal nocturnal hemoglobinuria (PNH, Marchiafava-Micheli syndrome)

Component of

• UDP-N-acetylglucosamine phosphatidylinositol transferase (GPI-GlcNAc transferase, GPI-GnT)

Database

• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=5277
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:5277
• OMIM: https://mirror.omim.org/entry/311770
• UniProt: http://www.uniprot.org/uniprot/P37287.html