AMN

AMN is a type I transmembrane protein. It is thought to modulate bone morphogenetic protein (BMP) receptor function by serving as an accessory or coreceptor, and thus facilitates or hinders BMP binding. It is known that the mouse AMN gene is expressed in

Full Name

Amnion Associated Transmembrane Protein

Function

Membrane-bound component of the endocytic receptor formed by AMN and CUBN (PubMed:14576052, PubMed:30523278, PubMed:29402915). Required for normal CUBN glycosylation and trafficking to the cell surface (PubMed:14576052, PubMed:29402915). The complex formed by AMN and CUBN is required for efficient absorption of vitamin B12 (PubMed:12590260, PubMed:14576052, PubMed:26040326). Required for normal CUBN-mediated protein transport in the kidney (Probable).

Biological Process

Cobalamin metabolic process Source: Reactome
Cobalamin transport Source: UniProtKB
Excretion Source: Ensembl
Golgi to plasma membrane protein transport Source: UniProtKB
High-density lipoprotein particle clearance Source: Reactome
Multicellular organism development Source: UniProtKB-KW
Protein localization Source: GO_Central
Receptor-mediated endocytosis Source: UniProtKB

Cellular Location

Isoform 1: Endosome membrane; Apical cell membrane; Cell membrane; Coated pit
Soluble protein amnionless: Secreted

Involvement in disease

Imerslund-Grasbeck syndrome 2 (IGS2): A form of Imerslund-Grasbeck syndrome, a rare autosomal recessive disorder characterized by vitamin B12 deficiency commonly resulting in megaloblastic anemia, which is responsive to parenteral vitamin B12 therapy and appears in infancy or early childhood. Clinical manifestations include failure to thrive, infections and neurological damage. Mild proteinuria, with no signs of kidney disease, is present in about half of the patients.

Topology

Extracellular: 20-357 aa
Helical: 358-378 aa
Cytoplasmic: 379-453 aa

PTM

N-glycosylated.
A soluble form arises by proteolytic removal of the membrane anchor.