Aryl hydrocarbon receptor

From Wikipedia, the free encyclopedia

aryl hydrocarbon receptor
Identifiers
Symbol	AHR
HUGO	348
Entrez	196
OMIM	600253
RefSeq	NM_001621
UniProt	P35869
Other data
Locus	Chr. 7 p15

Aryl hydrocarbon receptor or AhR is a basic-helix-loop-helix transcription factor that binds to HSP90 in the cytoplasm while inactivated. When bound to a signal agonist, such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), AhR moves to the nucleus and dimerizes with ARNT (AhR nuclear translocator), to modify transcription. The activated AhR binds to the Xenobiotic response element (XRE), a conserved DNA sequence known as an enhancer found upstream of many genes (see Targets of AhR).

1 Biological roles of AhR
2 Target genes of AhR
3 See also
4 External links

[edit] Biological roles of AhR

There is recent evidence suggesting that AhR plays a role in regulating hepatic (liver) cell regeneration. In experimental mice given the AhR agonist TCDD, AhR activity increased while the binding of Cyclin E to the Cyclin Dependent Kinase (CDK) complex decreased, halting the procession of hepatic cells from phase G1 to phase S of the cell cycle.

[edit] Target genes of AhR

Activation of AhR causes increased transcription of several cytochrome P450 genes in human, CYP1A1, CYP1A2,CYP1B1, and CYP2S1. These genes are important in the oxidative metabolism of drugs and many organic pollutants. Increased transcription of the Aryl hydrocarbon receptor repressor (AHRR) also occurs, a protein which inhibits AhR activity, allowing for only a transient activation of AhR.

[edit] See also

Reagent information by Bioreagents.com [1]
Mitchell K, Lockhart C, Huang G, Elferink C (2006). "Sustained aryl hydrocarbon receptor activity attenuates liver regeneration.". Mol Pharmacol 70 (1): 163-70. PMID 16636136.
Illustrations showing the activation and translocation of AhR [2]