Exostosin glycosyltransferase 1 (EXT1)

Exostosin glycosyltransferase 1 (EXT1) is a membrane-bound enzyme localized to the Golgi apparatus, responsible for catalyzing the polymerization of heparan sulfate chains by alternately adding N-acetylglucosamine and glucuronic acid units to growing proteoglycans. EXT1 usually functions as a heterodimeric complex with EXT2, forming an obligate assembly essential for normal heparan sulfate biosynthesis. EXT1 is regarded as a putative tumor suppressor, and mutations in its gene cause hereditary multiple exostoses, a disorder marked by benign bone tumors (osteochondromas), as well as other skeletal malformations in syndromes such as Trichorhinophalangeal syndrome type II. EXT1 is bi-functional, containing both GlcA-transferase and GlcNAc-transferase domains, but its GlcA-transferase activity is indispensable for the formation of heparan sulfate chains, and most disease-causing mutations cluster in its catalytic domain. The enzyme participates in key developmental and cellular processes, including regulation of cell signaling, angiogenesis, and blood coagulation.

Other names

Exostosin-1ttvExostosin glycosyltransferase 1Heparan sulfate co-polymerase subunit EXT1Multiple exostoses protein 1N-acetylglucosaminyl-proteoglycan 4-beta-glucuronosyltransferaseGlucuronosyl-N-acetylglucosaminyl-proteoglycan 4-alpha-N-acetylglucosaminyltransferaseEXTLGCRLGSTRPS2TTVexostoses (multiple) 1Langer-Giedion syndrome chromosome region protein