Olfactory receptor (IPR000725)

Short name: Olfact_rcpt

Overlapping homologous superfamilies


Family relationships


The olfactory system is a highly-specialised chemical recognition system that, like the immune system, is capable of discriminating with tremendous sensitivity between numerous foreign molecules in the environment. Olfactory transduction is believed to be initiated by the binding of odorants to specific receptor proteins in the cilia of olfactory receptor cells. Although little is known about the precise mechanism by which odorant binding might initiate membrane depolarisation, it is believed that cyclic AMP may serve as an intracellular messenger for olfactory transduction [PMID: 15335857].

Olfactory receptors are integral membrane proteins that belong to the seven transmembrane (TM), rhodopsin-like G-protein coupled receptor family. Although the sequences of these proteins are very diverse, reflecting to some extent their broad range of activating ligands, nevertheless, motifs have been identified in the TM regions that are characteristic of virtually the entire superfamily [PMID: 8386361, PMID: 8170923]. Amongst the exceptions are the olfactory receptors, which cluster together in a subfamily that lacks significant matches with TM domains 2, 4 and 6 [PMID: 8170923].

Olfactory receptor genes form the largest known multigene family in the human genome [PMID: 14507991]. Each olfactory receptor does not seem to detect a single odour. Instead, different odorants are recognised by different combinations of olfactory receptors [PMID: 10089886].

GO terms

Biological Process

GO:0007186 G protein-coupled receptor signaling pathway

Molecular Function

GO:0004984 olfactory receptor activity

Cellular Component

GO:0016021 integral component of membrane

Contributing signatures

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