Exostosin-like glycosyltransferase 3 (EXTL3)

Exostosin-like glycosyltransferase 3 (EXTL3) is a glycosyltransferase enzyme localized to the Golgi membrane, critical for the biosynthesis of heparan sulfate (HS), a glycosaminoglycan with diverse biological roles[2][1][4]. EXTL3 catalyzes the transfer of N-acetylglucosamine residues onto glycosaminoglycan precursor chains, specifically initiating HS synthesis and potentially elongating HS chains via GlcNAcT-I and GlcNAcT-II activities[4][2]. Unlike other exostosins, EXTL3 operates as a homodimer rather than requiring hetero-oligomerization and lacks glucuronyl transferase II (GlcAT-II) activity[1][3][4]. EXTL3 is necessary for normal skeletal development, hematopoiesis, immune regulation, and the maturation and function of pancreatic islets[2][4]. Mutations cause severe congenital disorders with immunological, skeletal, and neurologic symptoms. It has also been identified as a putative cell-surface receptor for regenerating islet-derived (REG) proteins, involved in tissue regeneration and immune responses, although this receptor function remains under active investigation and debate[2][4]. To date, there are no drugs that directly target EXTL3, but its activity and HS synthetic role are essential for normal cell function and development.

Other names

Exostosin-like 3EXTL1LEXTR1KIAA0519botvREGREXT-related protein 1Glucuronyl-galactosyl-proteoglycan 4-alpha-N-acetylglucosaminyltransferaseHereditary multiple exostoses gene isologMultiple exostosis-like protein 3Putative tumor suppressor protein EXTL3REG receptorISDNARPRexostosin-like 3EXT-related 1Epididymis secretory sperm binding proteinExostoses (multiple)-like 3Exostosin tumor-like 3EXT-related-1Exostosin-like glycosyltransferase 3

Not applicable as a direct drug target (primarily a biosynthetic enzyme; no direct pharmacological modulators known).