Aryl hydrocarbon receptor
From Wikipedia, the free encyclopedia
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aryl hydrocarbon receptor
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| Identifiers | |
| Symbol(s) | AHR |
| 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 (bHLH) 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 protein), to modify transcription. The activated AhR binds to the Xenobiotic response element (XRE), a conserved DNA sequence found in the promotor of several genes (see Targets of AhR).
[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 three cytochrome P450 genes, CYP1A1, CYP1A2, and CYP1B1. These genes are important in the Phase I response of drug metabolism. 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]
