Hypocretin (orexin) receptor 2


Orexin receptor type 2, also known as hypocretin receptor type 2, is a protein that in humans is encoded by the HCRTR2 gene. It should not be confused for the protein CD200R1 which shares the alias OX2R but is a distinct, unrelated gene located on the human chromosome 3.

Structure

The structure of the receptor has been solved to 2.5 Å resolution as a fusion protein bound to suvorexant using lipid-mediated crystallization.

Function

OX2 is a G-protein coupled receptor expressed exclusively in the brain. It has 64% identity with OX1. OX2 binds both orexin A and orexin B neuropeptides. OX2 is involved in the central feedback mechanism that regulates feeding behaviour. Mice with enhanced OX2 signaling are resistant to high-fat diet-induced obesity.
This receptor is activated by Hipocretin, which is a wake-promoting hypothalamic neuropeptide that acts as a critical regulator of sleep in animals as Zebrafish or Mammals. This protein has mutations in Astyanax mexicanus that reduces the sleep needs of the cavefish.

Ligands

Agonists

Antagonists