Prepro-orexin (IPR001704)

Short name: Orexin

Overlapping homologous superfamilies


Family relationships



Orexins (also known as hypocretins) are neuropeptides that are specifically localised to the hypothalamus. They are thought to interact with autonomic, neurendocrine and neuroregulatory systems, and play an important role in the regulation of feeding behaviour [PMID: 9892705, PMID: 9419374]. When applied to hypothalamic neurones, these peptides are neuroexcitatory, which action is probably mediated by their binding to a new family of G-protein-coupled receptors (orexin receptors 1 and 2), which were previously orphan [PMID: 9491897].

To date, two orexins have been characterised (orexin-A and -B), both encoded by a single mRNA transcript (prepro-orexin): orexin-A is a 33-residue peptide with two intramolecular disulphide bonds in the N-terminal region; and orexin-B is a linear 28-residue peptide. These peptides have 46% identity at the amino acid sequence level, and show some similarity to the glucagon/vasoactive intestinal polypeptide/secretin peptide family.

GO terms

Biological Process

GO:0007631 feeding behavior
GO:0007218 neuropeptide signaling pathway

Molecular Function

No terms assigned in this category.

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.