MGAT1: Mannosyl (Alpha-1,3-)-Glycoprotein Beta-1,2-N-Acetylglucosaminyltransferase
Key enzyme in N-glycan biosynthesis and congenital disorders of glycosylation
Gene Information Card
| Symbol | MGAT1 |
|---|---|
| Full Name | Mannosyl (Alpha-1,3-)-Glycoprotein Beta-1,2-N-Acetylglucosaminyltransferase |
| Gene Type | protein-coding |
| Chromosomal Location | 5q35.3 |
| NCBI Gene ID | 4245 ncbi.nlm.nih.gov/gene/4245 |
| Ensembl ID | ENSG00000131473 |
| UniProt ID | P26572 |
| OMIM ID | 160995 |
| HGNC ID | 7044 |
| Aliases | GGNT1, GLCNAC-TI, GNT-I, MGAT |
Description
MGAT1 encodes N-acetylglucosaminyltransferase I (GnT-I), a Golgi-resident enzyme that catalyzes the first committed step in the conversion of oligomannose to complex and hybrid N-glycans. This enzyme transfers N-acetylglucosamine from UDP-GlcNAc to the mannose residue of the Man5GlcNAc2 core structure. MGAT1 is essential for normal embryonic development and proper glycosylation of proteins. Mutations in MGAT1 cause congenital disorder of glycosylation type II (CDG II) and have been implicated in cancer progression.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Congenital disorder of glycosylation type II (MGAT1-CDG) | Loss-of-function mutations in MGAT1 impair N-glycan maturation, leading to multisystem developmental abnormalities. | OMIM #160995; ClinVar |
| Colorectal cancer | Altered MGAT1 expression affects N-glycan branching on cell surface receptors, influencing cell adhesion and metastasis. | COSMIC; PubMed studies |
| Hepatocellular carcinoma | Upregulation of MGAT1 correlates with increased complex N-glycans and poor prognosis. | COSMIC; PubMed studies |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Liver | 12.5 | Medium |
| Kidney | 9.8 | Medium |
| Brain | 7.2 | Low |
| Lung | 6.5 | Low |
| Colon | 11.3 | Medium |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HEK293 | 15.2 | High expression |
| HepG2 | 13.8 | High expression |
| HeLa | 10.1 | Medium expression |
| A549 | 8.5 | Medium expression |
| K562 | 4.3 | Low expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.661G>A (p.Gly221Arg) | Missense | Rare | Loss of enzymatic activity; associated with CDG II |
| c.1063C>T (p.Arg355Trp) | Missense | Rare | Reduced GnT-I activity; developmental delay |
| c.1201_1202del (p.Leu401fs) | Frameshift | Very rare | Complete loss of function; severe CDG phenotype |
Mutation functional classification
Loss of Function (LOF)
Most reported MGAT1 mutations are loss-of-function, leading to reduced or absent GnT-I activity and defective N-glycan processing.
Gain of Function (GOF)
No gain-of-function mutations have been documented in MGAT1.
Dominant Negative (DN)
No dominant-negative mutations have been reported for MGAT1.
View complete mutation data：
Gene Ontology (GO)
Pathways
• N-Glycan biosynthesis (Reactome: R-HSA-446203)
• Biosynthesis of the N-glycan precursor (KEGG: hsa00510)
• Protein glycosylation (UniProt: P26572)
Protein Summary
The MGAT1 protein (GnT-I) is a type II transmembrane glycoprotein localized to the Golgi apparatus. It consists of a short N-terminal cytoplasmic tail, a transmembrane domain, and a large C-terminal catalytic domain facing the Golgi lumen. GnT-I is essential for the synthesis of hybrid and complex N-glycans by adding a GlcNAc residue to the Man5GlcNAc2 core. The enzyme requires manganese ions as a cofactor. Structural studies reveal a GT-A fold with a conserved DXD motif critical for UDP-GlcNAc binding.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| MGAT1 Knockout HEK293 Cell Line | EDJ-KQ1872 | Human | 4245 | Details Get a Quote |
| MGAT1 Knockout A-549 Cell Line | EDJ-KQ23111 | Human | 4245 | Details Get a Quote |
| MGAT1 Knockout HCT 116 Cell Line | EDJ-KQ23113 | Human | 4245 | Details Get a Quote |
| MGAT1 Knockout HeLa Cell Line | EDJ-KQ23114 | Human | 4245 | Details Get a Quote |
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