POMT1
Protein O-Mannosyltransferase 1
Gene Information Card
| Symbol | POMT1 |
|---|---|
| Full Name | Protein O-Mannosyltransferase 1 |
| Gene Type | Protein coding |
| Chromosomal Location | 9q34.13 |
| NCBI Gene ID | 10585 ncbi.nlm.nih.gov/gene/10585 |
| Ensembl ID | ENSG00000130726 |
| UniProt ID | Q9Y6A1 |
| OMIM ID | 607423 |
| HGNC ID | 9202 |
| Aliases | LGMD2K, MDDGA4, MDDGB4, MDDGC4, POMT1-1, POMT1-2 |
Description
POMT1 encodes protein O-mannosyltransferase 1, an integral membrane protein of the endoplasmic reticulum that catalyzes the initial step of O-mannosyl glycosylation of alpha-dystroglycan. This post-translational modification is essential for the binding of alpha-dystroglycan to extracellular matrix proteins. Mutations in POMT1 cause a spectrum of dystroglycanopathies, including Walker-Warburg syndrome (WWS), limb-girdle muscular dystrophy type 2K (LGMD2K), and congenital muscular dystrophy with intellectual disability.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Walker-Warburg syndrome (WWS) | Loss-of-function mutations impair O-mannosylation of alpha-dystroglycan, disrupting basement membrane integrity in brain and muscle. | OMIM #236670; multiple case reports |
| Limb-girdle muscular dystrophy type 2K (LGMD2K) | Hypomorphic mutations reduce but do not abolish POMT1 activity, leading to milder muscular dystrophy with cognitive involvement. | OMIM #609308; ClinVar |
| Congenital muscular dystrophy with intellectual disability (MDDGA4/MDDGB4/MDDGC4) | Biallelic POMT1 mutations cause varying severity of muscle weakness, brain malformations, and eye anomalies. | OMIM #253280; NCBI GeneReviews |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Skeletal muscle | 14.2 | Medium |
| Heart | 11.8 | Medium |
| Brain | 9.5 | Low |
| Liver | 4.3 | Low |
| Kidney | 6.1 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HeLa | 12.5 | Cervical carcinoma |
| HepG2 | 8.9 | Hepatocellular carcinoma |
| K562 | 5.2 | Leukemia |
| A549 | 7.4 | Lung carcinoma |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1939G>A (p.Ala647Thr) | Missense | Found in LGMD2K families | Reduced enzymatic activity; hypomorphic |
| c.2167dupA (p.Thr723Asnfs*5) | Frameshift | Rare; associated with WWS | Loss of function; truncated protein |
| c.1465C>T (p.Arg489Trp) | Missense | Reported in MDDGA4 | Impaired substrate binding |
Mutation functional classification
Loss of Function (LOF)
Most pathogenic POMT1 mutations are loss-of-function, leading to reduced or absent O-mannosyltransferase activity and hypoglycosylation of alpha-dystroglycan.
Gain of Function (GOF)
No gain-of-function mutations have been reported for POMT1.
Dominant Negative (DN)
No dominant-negative mechanisms are described; POMT1-related disorders are autosomal recessive.
View complete mutation data：
Gene Ontology (GO)
| • mannosyltransferase activity (GO:0000030) | • endoplasmic reticulum (GO:0005783) |
| • protein glycosylation (GO:0006486) | • protein O-linked mannosylation (GO:0006493) |
| • integral component of membrane (GO:0016021) |
Pathways
• O-mannosyl glycan biosynthesis (Reactome: R-HSA-5173105)
• Dystroglycan-related disorders (KEGG: hsa05322)
Protein Summary
POMT1 is a 747-amino acid transmembrane protein localized to the endoplasmic reticulum. It forms a heteromeric complex with POMT2 to transfer mannose from dolichyl-phosphate-mannose to Ser/Thr residues of alpha-dystroglycan. This O-mannosylation is critical for the laminin-binding function of alpha-dystroglycan. Defects in POMT1 lead to hypoglycosylation of alpha-dystroglycan, causing a spectrum of congenital muscular dystrophies with brain and eye involvement.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| POMT1 Knockout HEK293 Cell Line | EDJ-KQ7096 | Human | 10585 | Details Get a Quote |
| POMT1 Knockout A-549 Cell Line | EDJ-KQ31946 | Human | 10585 | Details Get a Quote |
| POMT1 Knockout HCT 116 Cell Line | EDJ-KQ31947 | Human | 10585 | Details Get a Quote |
| POMT1 Knockout HeLa Cell Line | EDJ-KQ31948 | Human | 10585 | Details Get a Quote |
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