Aquaporin 3

Aquaporin 3 (AQP3) is a protein that in humans is encoded by the AQP3 gene. It is a member of the aquaporin family of water channels, which are integral membrane proteins that facilitate the transport of water across biological membranes.

Function

Aquaporin 3 is a glycerol-transporting protein that plays an important role in the regulation of water homeostasis in the body. It is expressed in various tissues, including the kidney, skin, lung, and gastrointestinal tract. In the kidney, AQP3 is found in the basolateral membrane of the collecting duct cells, where it facilitates the reabsorption of water. In the skin, it is involved in the hydration of the epidermis.

Structure

Like other aquaporins, AQP3 forms a tetramer in the membrane, with each monomer functioning as an independent water channel. Each monomer consists of six transmembrane alpha helices and two asparagine-proline-alanine (NPA) motifs that form the water pore.

Clinical significance

Mutations in the AQP3 gene have been associated with various diseases. For example, reduced expression of AQP3 has been observed in patients with diabetes insipidus, a condition characterized by excessive thirst and frequent urination. In contrast, overexpression of AQP3 has been linked to certain types of cancer, including melanoma and colorectal cancer.

Research

Research on AQP3 has focused on its role in water homeostasis and its potential as a therapeutic target for diseases associated with water imbalance. Studies have also investigated the regulation of AQP3 expression and its involvement in cell proliferation and migration.

See also

• Aquaporin
• Water channel
• Glycerol