Aryl Hydrocarbon Receptor Activation: From Coal to Dioxin

Aryl Hydrocarbon Receptor Activation

A constitutively active dioxin/aryl hydrocarbon receptor induces stomach tumors.

The dioxin/aryl hydrocarbon receptor (AhR) functions as a ligand-activated transcription factor regulating transcription of a battery of genes encoding xenobiotic metabolizing enzymes. Known receptor ligands are environmental pollutants including polycyclic aromatic hydrocarbons and polychlorinated dioxins. Loss-of-function (gene-disruption) studies in mice have demonstrated that the AhR is inv...

Calpain mediates the dioxin-induced activation and down-regulation of the aryl hydrocarbon receptor.

The aryl hydrocarbon receptor (AhR) is a ligand-activated basic-helix-loop-helix transcription factor that binds polyaromatic hydrocarbons (PAH), such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), and mediates their toxicity. Binding of PAH to AhR in the cytoplasm triggers a poorly defined transformation step of the receptor into a nuclear transcription factor. In this study, we show that the ...

Aryl hydrocarbon receptor activation inhibits regenerative growth.

There is considerable literature supporting the conclusion that inappropriate activation of the aryl hydrocarbon receptor (AHR) alters cellular signaling. We have established previously that fin regeneration is specifically inhibited by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in adult zebrafish and have used this in vivo endpoint to evaluate interactions between AHR and growth-controlling pa...

Comments on “Calpain Mediates the Dioxin-Induced Activation and Down-Regulation of the Aryl Hydrocarbon Receptor”

Dale and Eltom (2006) suggest that activation of the aryl hydrocarbon receptor (AHR)-signal transduction pathway is initiated after proteolytic processing of the AHR by calpain proteases. The authors propose that the calpains are activated by an increase in intracellular calcium that is initiated by ligand exposure. Although the hypotheses put forth by Dale and Eltom (2006) are very interesting...