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

When bound to toxic or non-toxic ligands, aryl hydrocarbon receptors (AhRs) are activated and nuclear translocation occurs; AhRs are bound to molecular chaperone complexes, AhR-HSP90-XAP2-p23 for toxic ligands, whereas for non-toxic ligands AhR-HSP90- XAP2 for non-toxic ligands. Toxic and non-toxic ligand selectivity of AhR depends on the components of the molecular chaperone complex. 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.
Source: FEBS Letters - Category: Biochemistry Authors: Tags: Research Letter Source Type: research