A4GNT (Alpha-1,4-N-Acetylglucosaminyltransferase)
Gene encoding a glycosyltransferase involved in mucin-type O-glycan biosynthesis and gastric mucosal protection.
Gene Information Card
| Symbol | A4GNT |
|---|---|
| Full Name | Alpha-1,4-N-Acetylglucosaminyltransferase |
| Gene Type | Protein coding |
| Chromosomal Location | 3q27.1 |
| NCBI Gene ID | 51146 ncbi.nlm.nih.gov/gene/51146 |
| Ensembl ID | ENSG00000163827 |
| UniProt ID | Q9UNA3 |
| OMIM ID | 607619 |
| HGNC ID | 17966 |
| Aliases | A4GNT1, alpha4GnT, GlcNAc-T |
Description
A4GNT encodes alpha-1,4-N-acetylglucosaminyltransferase, an enzyme that catalyzes the transfer of N-acetylglucosamine (GlcNAc) in alpha-1,4 linkage to the core 2 O-glycan structure on mucins. This modification is critical for the biosynthesis of gastric mucin (MUC6) and provides a protective barrier against Helicobacter pylori infection. The gene is predominantly expressed in the stomach and is implicated in gastric cancer and other gastrointestinal disorders.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Gastric cancer | Loss of A4GNT expression leads to altered mucin glycosylation, reducing mucosal barrier integrity and promoting H. pylori colonization, a risk factor for gastric carcinogenesis. | PMID: 19165226; NCBI Gene |
| Helicobacter pylori infection | A4GNT-dependent alpha-1,4-GlcNAc capping of mucin O-glycans inhibits H. pylori binding and growth; reduced activity increases susceptibility. | PMID: 15173114; UniProt |
| Peptic ulcer disease | Defective mucin glycosylation due to A4GNT deficiency compromises gastric mucosal defense, contributing to ulcer formation. | OMIM 607619 |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Stomach | 12.5 | Medium |
| Duodenum | 3.2 | Low |
| Colon | 1.8 | Low |
| Pancreas | 0.9 | Not detected |
| Liver | 0.5 | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| MKN45 (gastric cancer) | 15.3 | High expression |
| KATO III (gastric cancer) | 10.1 | Moderate expression |
| AGS (gastric adenocarcinoma) | 8.7 | Moderate expression |
| HeLa (cervical) | 0.2 | Not detected |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1A>G (p.Met1?) | Missense | <0.1% (gnomAD) | Likely loss of start codon, predicted loss of function |
| c.104C>T (p.Thr35Met) | Missense | 0.02% | Unknown significance; may affect enzyme activity |
| c.421G>A (p.Gly141Ser) | Missense | 0.01% | Reported in gastric cancer; potential loss of function |
Mutation functional classification
Loss of Function (LOF)
Mutations that disrupt the catalytic domain or start codon (e.g., p.Met1?) are predicted to reduce or abolish enzyme activity, impairing mucin glycosylation.
Gain of Function (GOF)
No gain-of-function mutations have been reported for A4GNT.
Dominant Negative (DN)
No dominant-negative mutations have been described for A4GNT.
View complete mutation data：
Gene Ontology (GO)
| • GO:0008376 (acetylglucosaminyltransferase activity) | • GO:0006486 (protein glycosylation) |
| • GO:0016266 (O-glycan processing) | • GO:0005794 (Golgi apparatus) |
| • GO:0005576 (extracellular region) |
Pathways
• REACT:21369 (Mucin O-glycan biosynthesis)
• KEGG:00512 (Mucin type O-glycan biosynthesis)
• Reactome: R-HSA-913709 (O-linked glycosylation of mucins)
Protein Summary
Alpha-1,4-N-acetylglucosaminyltransferase (UniProt Q9UNA3) is a 339-amino-acid type II transmembrane protein localized to the Golgi apparatus. It catalyzes the addition of alpha-1,4-linked GlcNAc to core 2 O-glycans on mucins, particularly MUC6. This modification is essential for gastric mucosal protection against H. pylori. The enzyme has a single transmembrane domain and a C-terminal catalytic domain facing the Golgi lumen.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| A4GNT Knockout HEK293 Cell Line | EDJ-KQ10953 | Human | 51146 | Details Get a Quote |
| A4GNT Knockout HeLa Cell Line | EDJ-KQ56235 | Human | 51146 | Details Get a Quote |
| A4GNT Knockout A-549 Cell Line | EDJ-KQ64725 | Human | 51146 | Details Get a Quote |
| A4GNT Knockout HCT 116 Cell Line | EDJ-KQ73170 | Human | 51146 | Details Get a Quote |
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