The Aryl Hydrocarbon Receptor: An Illuminating Effector of the UVB Response
Patrizia Agostinis1*,
Marjan Garmyn2, and
An Van Laethem1,2
1Department of Molecular and Cell Biology,
2Laboratory of Dermatology, Faculty of Medicine, Catholic University of Leuven, Herestraat 49, B-3000, Belgium.
Abstract:
The aryl hydrocarbon receptor (AhR) is a cytosolic ligand-activated transcription factor that mediates most of the toxic and carcinogenic effects of drugs and environmental toxins collectively known as xenobiotics. Ligand activation of the AhR stimulates the transcription of genes that encode several xenobiotic-metabolizing enzymes. The molecular mechanisms and signaling pathways evoked by the activation of the AhR are becoming increasingly understood and underscore the participation of the AhR in crucial processes, including cellular stress response, proliferation, differentiation, inflammation, and carcinogenesis. Studies now implicate the AhR as an integral part of the multifaceted signal transduction pathway initiated by the exposure of keratinocytes to ultraviolet B radiation (UVB), which is the most ubiquitous hazard to human skin and the principal risk factor for skin cancer. Ligand-dependent activation of the AhR in the cytosol provides a molecular bridge that links cytoplasmic events to nuclear signals, thus unmasking a previously unknown role for this transcription factor in the complex cellular response to UVB.
*Corresponding author. E-mail, Patrizia.Agostinis{at}med.kuleuven.be
