AQP8
Description
The AQP8 (aquaporin 8) is a protein-coding gene located on chromosome 16.
Aquaporin-8 is a protein encoded by the AQP8 gene in humans. It acts as a water channel protein and is a member of the aquaporin family, which is related to the major intrinsic protein. AQP-8 mRNA is found in the pancreas and colon but not in other tissues.
AQP8 is a channel protein that allows the passage of water and small uncharged molecules, such as hydrogen peroxide and ammonia, across cell membranes. It is found in various tissues, including the plasma membrane, inner mitochondrial membrane, and endoplasmic reticulum. AQP8 facilitates the transport of ammonia, which can also lead to proton transport, especially at alkaline pH. It may also transport ammonia analogs like formamide and methylamine. AQP8 does not transport urea or glycerol. Water transport is passive, driven by osmotic gradients, and sensitive to mercury and copper. In the liver, AQP8 mediates water transport towards the bile canaliculus, contributing to bile formation. It also releases hydrogen peroxide from mitochondria, impacting cholesterol synthesis, and facilitates ammonia uptake into mitochondria for urea production. In B cells, AQP8 moves hydrogen peroxide to the cytosol, promoting B cell activation. In the intestines, it helps with water transport in mitochondria and epithelial cell membranes. AQP8 may also play a role in the adaptation of kidney cells to acidic conditions by facilitating ammonia transport in mitochondria.
AQP8 is also known as AQP-8.
