Orexin receptor 2 (IPR004060)

Short name: Orexin_rcpt_2

Overlapping homologous superfamilies


Family relationships


The neuropeptide hormone orexin stimulates appetite and food consumption [PMID: 9656726], and is found in the hypothalamus, which has been shown to be the 'feeding centre' and plays a central role in the integrated control of feeding and energy homeostasis [PMID: 9491897]. It also has a prominent role in promoting wakefulness [PMID: 10458611, PMID: 10615891, PMID: 10481909]. The orexin receptor (also referred to as the hypocretin receptor) is a rhodopsin-like G protein-coupled receptor that binds orexin. There are two subtypes; orexin receptor 1 (OX1) and orexin receptor 2 (OX2) [PMID: 16507882].

This entry represents Orexin receptor 2, which is found throughout vertebrates and, like OX1, is expressed in brainstem and striatal nuclei, with additional expression in arousal promoting histaminergic nuclei [PMID: 9821961, PMID: 21216246, PMID: 11370008]. Both Orexin-A and B have nearly equal affinity for OX2 [PMID: 9491897], and stimulate intracellular calcium levels through OX2-mediated induction of Gq and phospholipase C activity, but is also capable of activating Gs, Gi, and potentially ion channels [PMID: 10498827, PMID: 12208495, PMID: 11600545, PMID: 11600545]. The OX2 receptor predominantly mediate the control of arousal induced by orexin neuropeptides [PMID: 12797957, PMID: 10458611].

GO terms

Biological Process

GO:0007186 G-protein coupled receptor signaling pathway
GO:0022410 circadian sleep/wake cycle process
GO:0007631 feeding behavior

Molecular Function

GO:0016499 orexin receptor activity

Cellular Component

GO:0016021 integral component of membrane

Contributing signatures

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