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. 2007 May 14;104(21):8851–8856. doi: 10.1073/pnas.0701764104

Fig. 2.

Fig. 2.

AhR controls epidermal growth factor receptor (EGFR) internalization and downstream signaling after UVB irradiation. (A) UVB irradiation (10 mJ/cm2) led to EGFR internalization with a disappearance from the cell membranes (arrow in sham control) and paranuclear accumulation (arrow in UVB irradiation) after 30 min. AhR knockdown (KO) prevented EGFR internalization (arrow indicates EGFR at the cell membrane; N indicates nuclei). (Scale bar, 20 μm.) (B) Western blot analyses of the EGFR downstream target ERK1/2 revealed UVB-induced ERK1/2 phosphorylation that is partially AhR-dependent because it is antagonized by AhR knockdown. Cells transduced with nonsilencing AhR shRNA (AhR n.s.) showed no effect on ERK1/2 phosphorylation compared with the vector controls. (C) Real-time RT-PCR demonstrated an inhibition of the UVB-induced COX-2 mRNA induction in AhR KO HaCaT cells compared with the vector or AhR n.s. transduced HaCaTs. (D) COX-2 Western blot shows a reduction of COX-2 protein induction after UVB irradiation in AhR KO cells compared with the vector and n.s. controls. ∗∗, P < 0.01.