Vitamin D receptor: molecular signaling and actions of nutritional ligands in disease prevention.

The human vitamin D receptor (VDR) is a key nuclear receptor that binds nutritionally derived ligands and exerts bioeffects that contribute to bone mineral homeostasis, detoxification of exogenous and endogenous compounds, cancer prevention, and mammalian hair cycling. Liganded VDR modulates gene expression via heterodimerization with the retinoid X receptor and recruitment of coactivators or corepressors. VDR interacts with the corepressor hairless (Hr) to control hair cycling, an action independent of the endocrine VDR ligand, 1,25-dihydroxyvitamin D(3). We report novel dietary ligands for VDR including curcumin, gamma-tocotrienol, and essential fatty acid derivatives that likely play a role in the bioactions of VDR.