The components of the AhR‐molecular chaperone complex differ depending on whether the ligands are toxic or non‐toxic

Abstract

The aryl hydrocarbon receptor (AhR) forms a complex with the HSP90‐XAP2‐p23 molecular chaperone when the cells are exposed to toxic compounds. Recently, 1,4‐dihydroxy‐2‐naphthoic acid (DHNA) was reported to be an AhR ligand. Here, we investigated the components of the molecular chaperone complex when DHNA binds to AhR. Proteins eluted from the 3‐Methylcolanthrene‐affinity column were AhR‐HSP90‐XAP2‐p23 complex. The AhR‐molecular chaperone complex did not contain p23 in the eluents from the DHNA‐affinity column. In 3‐MC‐treated cells, AhR formed a complex with HSP90‐XAP2‐p23 and nuclear translocation occurred within 30 min, while in DHNA‐treated cells, AhR formed a complex with AhR‐HSP90‐XAP2, and translocation was slow from 60 min. Thus, the AhR activation mechanism may differ when DHNA is the ligand compared to toxic ligands.