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ScopeEdit

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. GPCRs are usually described as "superfamily" because 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.[2] The currently known superfamily members include the rhodopsin-like GPCRs (this family), the secretin-like GPCRs, the cAMP receptors, the fungal mating pheromone receptors, and the metabotropic glutamate receptor family. There is a specialised database for GPCRs.[3]

FunctionEdit

The rhodopsin-like GPCRs themselves represent a widespread protein family that includes hormones, neurotransmitters, 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.[4][5][6]

ClassesEdit

Rhodopsin-like GPCRs have been classified into the following 19 subgroups (A1-A19) based on a phylogenetic analysis.[7]

Subfamily A1Edit

Subfamily A2Edit

Subfamily A3Edit

Subfamily A4Edit

Subfamily A5Edit

Subfamily A6Edit

Subfamily A7Edit

Subfamily A8Edit

Subfamily A9Edit

Subfamily A10Edit

Subfamily A11Edit

Subfamily A12Edit

Subfamily A13Edit

Subfamily A14Edit

Subfamily A15Edit

Subfamily A16Edit

Subfamily A17Edit

Subfamily A18Edit

Subfamily A19Edit

UnclassifiedEdit

ReferencesEdit

  1. ^ Palczewski K, Kumasaka T, Hori T, et al. (August 2000). "Crystal structure of rhodopsin: A G protein-coupled receptor". Science. 289 (5480): 739–45. doi:10.1126/science.289.5480.739. PMID 10926528.
  2. ^ a b Attwood TK, Findlay JB (1994). "Fingerprinting G-protein-coupled receptors". Protein Eng. 7 (2): 195–203. doi:10.1093/protein/7.2.195. PMID 8170923.
  3. ^ "Information system for G protein-coupled receptors". GPCRDB. www.gpcr.org. Archived from the original on 2009-04-22. Retrieved 2008-12-05.
  4. ^ Birnbaumer L (1990). "G proteins in signal transduction". Annu. Rev. Pharmacol. Toxicol. 30: 675–705. doi:10.1146/annurev.pa.30.040190.003331. PMID 2111655.
  5. ^ Gilman AG, Casey PJ (1988). "G protein involvement in receptor-effector coupling". J. Biol. Chem. 263 (6): 2577–2580. PMID 2830256.
  6. ^ Attwood TK, Findlay JB (1993). "Design of a discriminating fingerprint for G-protein-coupled receptors". Protein Eng. 6 (2): 167–176. doi:10.1093/protein/6.2.167. PMID 8386361.
  7. ^ Joost P, Methner A (2002). "Phylogenetic analysis of 277 human G-protein-coupled receptors as a tool for the prediction of orphan receptor ligands". Genome Biol. 3 (11): research0063.1–0063.16. doi:10.1186/gb-2002-3-11-research0063. PMC 133447. PMID 12429062.
  8. ^ Terakita A (2005). "The opsins". Genome Biol. 6 (3): 213. doi:10.1186/gb-2005-6-3-213. PMC 1088937. PMID 15774036.
  9. ^ a b Nordström KJ, Sällman Almén M, Edstam MM, Fredriksson R, Schiöth HB (September 2011). "Independent HHsearch, Needleman—Wunsch-based, and motif analyses reveal the overall hierarchy for most of the G protein-coupled receptor families". Molecular Biology and Evolution. 28 (9): 2471–80. doi:10.1093/molbev/msr061. PMID 21402729.

External linksEdit