AMN Gene (Amnion Associated Transmembrane Protein)
Key regulator of vitamin B12 absorption and transport
Gene Information Card
| Symbol | AMN |
|---|---|
| Full Name | Amnion Associated Transmembrane Protein |
| Gene Type | Protein coding |
| Chromosomal Location | 14q32.33 |
| NCBI Gene ID | 81693 ncbi.nlm.nih.gov/gene/81693 |
| Ensembl ID | ENSG00000166126 |
| UniProt ID | Q9BXJ7 |
| OMIM ID | 605799 |
| HGNC ID | 14604 |
| Aliases | PRO1028, amnionless |
Description
The AMN gene encodes amnionless, a transmembrane protein essential for the absorption of vitamin B12 (cobalamin) in the ileum. It forms a receptor complex with cubilin (CUBN) to mediate endocytosis of the intrinsic factor-vitamin B12 complex. Mutations in AMN cause Imerslund-Gräsbeck syndrome (IGS), characterized by megaloblastic anemia and proteinuria.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Imerslund-Gräsbeck syndrome (IGS) | Defective AMN impairs cubilin-mediated endocytosis of intrinsic factor-vitamin B12 complex, leading to B12 deficiency | ClinVar, OMIM |
| Megaloblastic anemia | Secondary to vitamin B12 malabsorption due to AMN dysfunction | ClinVar |
| Proteinuria | Associated with cubilin dysfunction in renal tubules; AMN mutations disrupt receptor recycling | OMIM |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Kidney | 12.5 | Medium |
| Small intestine | 8.3 | Medium |
| Liver | 4.1 | Low |
| Placenta | 3.8 | Low |
| Testis | 2.9 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HEK 293 | 15.2 | Moderate expression |
| Caco-2 | 10.5 | Intestinal epithelial model |
| HepG2 | 5.0 | Hepatocellular carcinoma |
| A549 | 2.1 | Lung carcinoma |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.208C>T (p.Arg70*) | Nonsense | Rare | Loss of function; truncated protein |
| c.349G>A (p.Gly117Arg) | Missense | Rare | Impaired cubilin binding |
| c.425_426del (p.Leu142fs) | Frameshift | Rare | Loss of function; premature stop |
Mutation functional classification
Loss of Function (LOF)
Most AMN mutations are loss-of-function, leading to defective vitamin B12 absorption and IGS.
Gain of Function (GOF)
No gain-of-function mutations reported.
Dominant Negative (DN)
No dominant-negative mutations reported; IGS is autosomal recessive.
View complete mutation data：
Gene Ontology (GO)
| • GO:0005886 | • GO:0016021 |
| • GO:0006898 | • GO:0031410 |
| • GO:0005509 | • GO:0005769 |
Pathways
• Vitamin B12 metabolism (Reactome: R-HSA-196741)
• Cubilin-mediated endocytosis (Reactome: R-HSA-2173782)
Protein Summary
Amnionless is a 453-amino acid transmembrane protein that localizes to the apical membrane of intestinal and renal epithelial cells. It forms a stable complex with cubilin, facilitating the endocytosis of the intrinsic factor-vitamin B12 complex. The protein contains a signal peptide, a transmembrane domain, and a cytoplasmic tail involved in receptor recycling. Defects in AMN disrupt this process, causing vitamin B12 malabsorption.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| AMN Knockout HEK293 Cell Line | EDJ-KQ9741 | Human | 81693 | Details Get a Quote |
| AMN1 Knockout HEK293 Cell Line | EDJ-KQ12341 | Human | 196394 | Details Get a Quote |
| AMN1 Knockout HeLa Cell Line | EDJ-KQ39934 | Human | 196394 | Details Get a Quote |
| AMN1 Knockout A-549 Cell Line | EDJ-KQ41192 | Human | 196394 | Details Get a Quote |
| AMN1 Knockout HCT 116 Cell Line | EDJ-KQ41193 | Human | 196394 | Details Get a Quote |
| AMN Knockout HeLa Cell Line | EDJ-KQ57406 | Human | 81693 | Details Get a Quote |
| AMN Knockout A-549 Cell Line | EDJ-KQ65914 | Human | 81693 | Details Get a Quote |
| AMN Knockout HCT 116 Cell Line | EDJ-KQ74340 | Human | 81693 | Details Get a Quote |
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