AQP7

Aquaporin 7 (AQP7) is a protein that in humans is encoded by the AQP7 gene. It belongs to the aquaporin family, a group of small, integral membrane proteins that facilitate water transport across the membranes of cells. AQP7 is particularly important in the transport of glycerol and water in and out of cells, playing a crucial role in metabolism and energy balance.

Function

AQP7 is expressed primarily in the adipose tissue, kidney, and testis, where it facilitates the bidirectional transport of glycerol and water. In adipose tissue, AQP7 helps in the mobilization of glycerol, which is a major substrate for gluconeogenesis in the liver during fasting. This process is vital for maintaining blood glucose levels. In the kidney, AQP7's role in water reabsorption contributes to the regulation of water balance and blood pressure.

Clinical Significance

Alterations in AQP7 expression or function have been linked to several metabolic disorders. For instance, reduced AQP7 levels in adipose tissue are associated with obesity and type 2 diabetes, conditions characterized by impaired glycerol release and altered glucose homeostasis. Furthermore, mutations in the AQP7 gene can lead to rare genetic conditions affecting glycerol metabolism.

Genetic and Molecular Aspects

The AQP7 gene is located on chromosome 9 in humans. The protein encoded by this gene consists of six membrane-spanning domains with both N-terminal and C-terminal located intracellularly, a structure characteristic of the aquaporin family. Regulation of AQP7 expression is complex and can be influenced by nutritional status, hormones, and other factors that impact metabolism.

Research Directions

Ongoing research is focused on elucidating the detailed mechanisms by which AQP7 contributes to energy homeostasis and metabolic health. Studies are also exploring the potential of targeting AQP7 in the treatment of metabolic diseases, such as obesity and diabetes, through pharmacological agents or genetic interventions.