Vitamin D receptor

Vitamin D receptor (VDR) is a member of the nuclear receptor family of transcription factors. Upon activation by vitamin D, the VDR forms a heterodimer with the retinoid-X receptor and binds to hormone response elements on DNA resulting in expression or transrepression of specific gene products.

Function

The VDR is involved in cell proliferation and differentiation. Vitamin D and its analogs modulate a variety of biological responses, inhibiting the growth of malignant cells, modulating the immune response, and regulating differentiation of normal and malignant cells. The VDR is expressed in a large number of tissues including the bone, intestine, kidney, colon, brain cells, immune cells, and breast tissue.

Structure

The VDR belongs to the family of trans-acting transcriptional regulatory factors. The receptor has a DNA-binding domain (DBD), and a ligand binding domain (LBD). The DBD is highly conserved among the various nuclear receptors, while the LBD is more specific, defining the individuality of each receptor.

Clinical significance

Mutations in the VDR gene are associated with rickets, a disease caused by vitamin D deficiency. In addition, polymorphisms in the VDR gene have been linked to an increased risk of autoimmune diseases, including type 1 diabetes, multiple sclerosis, and rheumatoid arthritis.

See also

• Vitamin D
• Nuclear receptor
• Transcription factor
• Rickets