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AMN

Domain

The complex formed by AMN and CUBN is composed of a 400 Angstrom long stem and a globular crown region. The stem region is probably formed by AMN and the CUBN N-terminal region, including the EGF-like domains. The crown is probably formed by the CUBN CUB domains.

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).

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.

None

The disease is caused by variants affecting the gene represented in this entry.

Post-translational modifications

N-glycosylated.

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

Tissue specificity

Detected in proximal tubules in the kidney cortex (at protein level) (PubMed:14576052, PubMed:29402915). Long isoforms are highly expressed in small intestine, colon and kidney (renal proximal tubule epithelial cells). Shorter isoforms are detected at lower levels in testis, thymus and peripheral blood leukocytes.

Cellular localization

  • Isoform 1
  • Apical cell membrane
  • Single-pass type I membrane protein
  • Cell membrane
  • Single-pass type I membrane protein
  • Endosome membrane
  • Membrane
  • Coated pit
  • Soluble protein amnionless
  • Secreted

Alternative names

  • Protein amnionless
  • UNQ513/PRO1028
  • AMN

Target type

Proteins

Molecular weight

0Da