Transferrin receptor 2

Transferrin receptor 2 (TfR2) is a protein that plays a crucial role in iron metabolism. It is encoded by the TFRC2 gene and is primarily expressed in the liver. TfR2 is involved in the regulation of iron uptake and storage, making it an essential component of the body's iron homeostasis.

Structure

The TfR2 protein consists of a single polypeptide chain with a molecular weight of approximately 90 kDa. It is composed of three main domains: an extracellular domain, a transmembrane domain, and a cytoplasmic domain. The extracellular domain is responsible for binding to transferrin, a glycoprotein that transports iron in the bloodstream.

Function

TfR2 functions as a receptor for transferrin, facilitating the uptake of iron into cells. Unlike its closely related counterpart, transferrin receptor 1 (TfR1), TfR2 has a lower affinity for transferrin. This suggests that TfR2 may have a specialized role in iron metabolism, particularly in the liver.

One of the key functions of TfR2 is its involvement in the regulation of hepcidin, a hormone that controls iron levels in the body. TfR2 signaling in the liver leads to the suppression of hepcidin production, allowing for increased iron absorption from the diet and enhanced release of stored iron from cells.

Clinical Significance

Mutations in the TFRC2 gene have been associated with a rare genetic disorder known as hereditary hemochromatosis type 3 (HH3). HH3 is characterized by excessive iron accumulation in various organs, leading to tissue damage and dysfunction. The impaired function of TfR2 in individuals with HH3 disrupts the normal regulation of iron metabolism, resulting in iron overload.

Understanding the role of TfR2 in iron metabolism has significant implications for the diagnosis and treatment of iron-related disorders. Further research into the molecular mechanisms underlying TfR2 function may provide insights into potential therapeutic targets for conditions such as hereditary hemochromatosis and other iron-related diseases.

See Also

• Transferrin receptor 1
• Iron metabolism
• Hepcidin