EDG-8 sphingosine 1-phosphate receptor (IPR005386)

Short name: EDG8_S1P_rcpt

Overlapping homologous superfamilies


Family relationships


G protein-coupled receptors (GPCRs) constitute a vast protein family that encompasses a wide range of functions, including various autocrine, paracrine and endocrine processes. They show considerable diversity at the sequence level, on the basis of which they can be separated into distinct groups [PMID: 12679517]. The term clan can be used to describe the GPCRs, as they embrace a group of families for which there are indications of evolutionary relationship, but between which there is no statistically significant similarity in sequence [PMID: 8170923]. The currently known clan members include rhodopsin-like GPCRs (Class A, GPCRA), secretin-like GPCRs (Class B, GPCRB), metabotropic glutamate receptor family (Class C, GPCRC), fungal mating pheromone receptors (Class D, GPCRD), cAMP receptors (Class E, GPCRE) and frizzled/smoothened (Class F, GPCRF) [PMID: 8170923, PMID: 8081729, PMID: 15914470, PMID: 18948278, PMID: 16753280]. GPCRs are major drug targets, and are consequently the subject of considerable research interest. It has been reported that the repertoire of GPCRs for endogenous ligands consists of approximately 400 receptors in humans and mice [PMID: 12679517]. Most GPCRs are identified on the basis of their DNA sequences, rather than the ligand they bind, those that are unmatched to known natural ligands are designated by as orphan GPCRs, or unclassified GPCRs [PMID: 23020293].

The rhodopsin-like GPCRs (GPCRA) represent a widespread protein family that includes hormone, neurotransmitter and light receptors, all of which transduce extracellular signals through interaction with guanine nucleotide-binding (G) proteins. Although their activating ligands vary widely in structure and character, the amino acid sequences of the receptors are very similar and are believed to adopt a common structural framework comprising 7 transmembrane (TM) helices [PMID: 2111655, PMID: 2830256, PMID: 8386361].

Sphingosine 1-phosphate (S1P) is released from activated platelets and is also produced by a number of other cell types in response to growth factors and cytokines [PMID: 11150592]. It is proposed to act both as an extracellular mediator and as an intracellular second messenger. Recently, 5 G protein-coupled receptors have been identified that act as high affinity receptors for S1P and also as low affinity receptors for the related lysophospholipid, SPC [PMID: 11264467]. EDG-1, EDG-3, EDG-5 and EDG-8 share a high degree of similarity and are also referred to as lpB1, lpB3, lpB2 and lpB4, respectively. EDG-6 is referred to as lpC1, reflecting its more distant relationship to the other S1P receptors.

EDG-8 is expressed predominantly in the white matter tracts of the brain and in the pancreas [PMID: 11150592]. Upon binding of S1P, EDG-8 appears to couple to Gi and G12 proteins but not Gq family members. Unlike other EDG receptors, which activate MAP kinases and stimulate proliferation, EDG-8 causes inhibition of ERK MAP kinases and proliferation, and also inhibition of adenylyl cyclase [PMID: 1106989].

GO terms

Biological Process

GO:0007186 G protein-coupled receptor signaling pathway

Molecular Function

GO:0038036 sphingosine-1-phosphate receptor activity

Cellular Component

GO:0016021 integral component of membrane

Contributing signatures

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