The AMN gene provides instructions for making a protein called amnionless that spans the membranes of cells in the intestines and the kidneys. Amnionless helps the body absorb vitamin B12 (also called cobalamin) from food, which is important because the body cannot make this vitamin. Vitamin B12 is essential for the formation of DNA and for the chemical reactions that convert food into energy (energy metabolism). Vitamin B12 also plays a key role in making red blood cells and maintaining the nerve cells in the brain and spinal cord (central nervous system).
Amnionless binds to another protein called cubilin to form a complex called the cubam receptor. In the small intestine, cubilin can interact with vitamin B12 while it is anchored to the cell membrane by amnionless.
During digestion, vitamin B12 binds to intrinsic factor, which helps the intestines absorb vitamin B12. Vitamin B12 and intrinsic factor then bind to cubilin as they pass through the small intestine. Amnionless helps transfer this whole complex into the intestinal cells. Vitamin B12 is then released into the blood and travels throughout the body. In the kidneys, amnionless and cubilin help return proteins to the bloodstream (reabsorption) that would otherwise be released in the urine.
Other Names
amnionless
Related Genetics Topics
Identifiers
- NCBI Gene: 81693
- OMIM: 605799
Source: MedlinePlus Genetics, U.S. National Library of Medicine.
