EXTL1: Exostosin Like Glycosyltransferase 1
A key enzyme in heparan sulfate biosynthesis with implications in skeletal development and tumor suppression.
Gene Information Card
| Symbol | EXTL1 |
|---|---|
| Full Name | Exostosin Like Glycosyltransferase 1 |
| Gene Type | Protein coding |
| Chromosomal Location | 1p36.11 |
| NCBI Gene ID | 7157 ncbi.nlm.nih.gov/gene/7157 |
| Ensembl ID | ENSG00000117525 |
| UniProt ID | Q92935 |
| OMIM ID | 191170 |
| HGNC ID | 3515 |
| Aliases | EXTL, EXTL1L, FLJ12681 |
Description
EXTL1 encodes a member of the exostosin-like family of glycosyltransferases involved in heparan sulfate biosynthesis. The protein catalyzes the addition of N-acetylglucosamine to the heparan sulfate chain. Mutations in this gene are associated with hereditary multiple exostoses (HME) and may play a role in tumor suppression.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Hereditary Multiple Exostoses (HME) | Loss-of-function mutations in EXTL1 disrupt heparan sulfate elongation, leading to abnormal bone growth and osteochondroma formation. | OMIM 191170; NCBI Gene |
| Exostosis | Deficient EXTL1 activity impairs heparan sulfate proteoglycan signaling, promoting cartilage cap formation. | ClinVar; NCBI Gene |
| Chondrosarcoma (rare) | Somatic mutations in EXTL1 may contribute to malignant transformation of exostoses. | COSMIC; NCBI Gene |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Brain | 12.5 | Low |
| Heart | 8.3 | Low |
| Liver | 3.1 | Not detected |
| Kidney | 15.2 | Low |
| Testis | 45.7 | Medium |
| Thyroid | 22.1 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HEK 293 | 18.4 | Embryonic kidney cells; moderate expression |
| HeLa | 9.7 | Cervical carcinoma; low expression |
| HepG2 | 5.2 | Hepatocellular carcinoma; low expression |
| K562 | 3.8 | Leukemia; very low expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1072C>T (p.Arg358*) | Nonsense | <0.1% | Premature stop; loss of function |
| c.1435G>A (p.Gly479Arg) | Missense | <0.1% | Impaired catalytic activity |
| c.1666_1667del (p.Gln556fs) | Frameshift | <0.1% | Truncated protein; loss of function |
Mutation functional classification
Loss of Function (LOF)
Nonsense and frameshift mutations (e.g., p.Arg358*, p.Gln556fs) lead to truncated, non-functional EXTL1 protein, disrupting heparan sulfate elongation.
Gain of Function (GOF)
No gain-of-function mutations reported for EXTL1.
Dominant Negative (DN)
No dominant-negative mutations reported for EXTL1.
View complete mutation data：
Gene Ontology (GO)
Pathways
• Heparan sulfate biosynthesis (Reactome: R-HSA-2022928)
• Glycosaminoglycan metabolism (KEGG: hsa00532)
Protein Summary
EXTL1 is a type II transmembrane glycosyltransferase localized to the Golgi apparatus. It catalyzes the transfer of N-acetylglucosamine to the heparan sulfate chain, a critical step in heparan sulfate proteoglycan synthesis. The protein is 676 amino acids long and contains a conserved glycosyltransferase domain. Loss of EXTL1 function leads to defective heparan sulfate elongation, contributing to hereditary multiple exostoses and potentially tumor suppression.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| EXTL1 Knockout HEK293 Cell Line | EDJ-KQ4566 | Human | 2134 | Details Get a Quote |
| EXTL1 Knockout HeLa Cell Line | EDJ-KQ53182 | Human | 2134 | Details Get a Quote |
| EXTL1 Knockout A-549 Cell Line | EDJ-KQ61663 | Human | 2134 | Details Get a Quote |
| EXTL1 Knockout HCT 116 Cell Line | EDJ-KQ70144 | Human | 2134 | Details Get a Quote |
