Exostosin-like (IPR004263)

Short name: Exostosin

Overlapping homologous superfamilies


Family relationships


There are five identified human EXT family proteins (EXT1, EXT2, EXTL1, EXTL2 and EXTL3), which are members of the hereditary multiple exostoses family of tumor suppressors [PMID: 17237233]. They are glycosyltransferases required for the biosynthesis of heparan sulfate. Hereditary multiple exostoses (EXT) is an autosomal dominant disorder that is characterised by the appearance of multiple outgrowths of the long bones (exostoses) at their epiphyses [PMID: 9473480]. Mutations in two homologous genes, EXT1 and EXT2, are responsible for the EXT syndrome. The human and mouse EXT genes have at least two homologues in the invertebrate Caenorhabditis elegans, indicating that they do not function exclusively as regulators of bone growth. EXT1 and EXT2 have both been shown to encode glycosyltransferases involved in the chain elongation step of heparan sulphate biosynthesis [PMID: 9756849].

This entry also includes Arabidopsis Xyloglucan galactosyltransferase KATAMARI1 [PMID: 12837954] and Drosophila melanogaster EXT homologues [PMID: 14998928].

GO terms

Biological Process

GO:0006486 protein glycosylation

Molecular Function

GO:0016757 transferase activity, transferring glycosyl groups

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.