AIP(redirected from XAP2)
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AIPacute intermittent porphyria.
acute intermittent porphyria (AIP)
an autosomal-dominant, genetically transmitted metabolic hepatic disorder characterized by acute attacks of neurological dysfunction that can be started by environmental or endogenous factors. Women are affected more frequently than men, and attacks often are precipitated by starvation or severe dieting, alcohol ingestion, bacterial or viral infections, and a wide range of pharmaceutical products. Any part of the nervous system can be affected, and an initial common effect is mild to severe abdominal pain. Other effects can include tachycardia, hypertension, hyponatremia, peripheral neuropathy, and organic brain dysfunction marked by seizures, coma, hallucinations, and respiratory paralysis. A frequent diagnostic factor is a high level of porphyrin precursors in the urine, which usually increases during periods of acute attacks. Treatment is generally symptomatic, with emphasis on respiratory support, beta-blockers, and pain control. Education of the patient focuses on environmental factors, particularly medications such as barbiturates, that are known to cause an onset of symptoms, as well as avoidance of alcohol, sunlight, and skin trauma. A high-carbohydrate diet is reported to reduce the risk of acute attacks because glucose tends to block the induction of hepatic gamma-aminolevulinic acid synthetase, an enzyme involved in the porphyrias. See also porphyria.
AIP(1) A 330 residue protein that helps stabilise the AIP-hsp90-AhR complex and protects the AhR receptor from ubiquitination under heat-stress conditions; AIP may also play a role in regulating the rate of AhR turnover by delaying AhR nuclear translocation after ligand binding.
(2) A gene on chromosome 11q13.3 that encodes a receptor for aryl hydrocarbons and a ligand-activated transcription factor. It resides in the cytoplasm as part of a multiprotein complex and is transported to the nucleus once it binds with a ligand. AIP regulates the expression of many xenobiotic metabolising enzymes; it binds specifically to and inhibits the activity of hepatitis B virus.