A bile acid transport protein, also known as a bile acid transporter, is a biological protein that plays a crucial role in the transportation of bile acids throughout the body. Bile acids are synthesized in the liver and are essential for the digestion and absorption of dietary fats. They also play a significant role in cholesterol metabolism.
These transport proteins are primarily located on the plasma membrane of cells in the liver, intestine, and kidneys. They facilitate the uptake and secretion of bile acids across various cellular membranes, thus maintaining the necessary balance of bile acid concentrations within the body.
Bile acid transport proteins belong to the superfamily of ATP-binding cassette (ABC) transporters. These proteins employ the energy from adenosine triphosphate (ATP) hydrolysis to actively transport bile acids across the plasma membrane. They exhibit high specificity for bile acids and can differentiate between different types of bile acids based on their chemical structure.
By transporting bile acids, these proteins contribute to maintaining bile acid homeostasis, preventing the accumulation of toxic levels of bile acids within tissues. They regulate the enterohepatic circulation of bile acids, ensuring that an adequate amount of bile acids is reabsorbed in the small intestine and returned to the liver via the portal vein.
Disruptions or mutations in bile acid transport proteins may lead to pathological conditions, such as cholestasis, where the flow of bile is impaired, resulting in the accumulation of bile acids in the liver and bloodstream. Inhibiting or enhancing the activity of bile acid transport proteins has been explored as a potential therapeutic target for liver and metabolic disorders.
