Description
aryl hydrocarbon receptor-associated protein-9 (ARA9), also known as AIP or XAP-2, is a protein that in humans is encoded by the AIP gene. This gene is mapped to 11q13.2. The encoded protein is found in the cytoplasm as part of a multiprotein complex, but upon binding of ligand is transported to the nucleus. ARA9/AIP may play a positive role in aryl hydrocarbon receptor-mediated signalling possibly by influencing its receptivity for ligand and/or its nuclear targeting. It has been shown that ARA9 is the cellular negative regulator of the hepatitis B virus (HBV) X protein. Mutations may be the cause of a familial form of acromegaly, familial isolated pituitary adenoma (FIPA)