Nuclear receptor

Crystallographic structure of a heterodimer of the nuclear receptors PPAR-γ (green) and RXR-α (cyan) bound to double stranded DNA (magenta) and two molecules of the NCOA2 coactivator (red). The PPAR-γ antagonist GW9662 and RXR-α agonist retinoic acid are depicted as space-filling models (carbon = white, oxygen = red, nitrogen = blue, chlorine = green).[1]

In the field of molecular biology, nuclear receptors are a class of proteins responsible for sensing steroids, thyroid hormones, vitamins, and certain other molecules. These intracellular receptors work with other proteins to regulate the expression of specific genes, thereby controlling the development, homeostasis, and metabolism of the organism.

Nuclear receptors bind directly to DNA regulating the expression of adjacent genes; hence these receptors are classified as transcription factors.[2][3] The regulation of gene expression by nuclear receptors often occurs in the presence of a ligand—a molecule that affects the receptor's behavior. Ligand binding to a nuclear receptor results in a conformational change activating the receptor. The result is up- or down-regulation of gene expression.

A unique property of nuclear receptors that differentiates them from other classes of receptors is their direct control of genomic DNA. Nuclear receptors play key roles in both embryonic development and adult homeostasis. As discussed below, nuclear receptors are classified according to mechanism[4][5] or homology.[6][7]

  1. ^ Cite error: The named reference Chandra_2008 was invoked but never defined (see the help page).
  2. ^ Cite error: The named reference Evans_1988 was invoked but never defined (see the help page).
  3. ^ Cite error: The named reference Olefsky_2001 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference Mangelsdorf_1995 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference Novac_2004 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference NRNC_1999 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference Laudet_1997 was invoked but never defined (see the help page).