Secretin receptor family

Secretin family of 7 transmembrane receptors is a family of evolutionarily related proteins.^[1]

This family is known as Family B, the secretin-receptor family or family 2 of the G-protein-coupled receptors.They have been described in many animal species, but not in plants, fungi or prokaryotes. Three distinct sub-families (B1-B3) are recognized. Many secretin receptors are regulated by peptide hormoness from the glucagon hormone family.

The secretin-like GPCRs include secretin, calcitonin, parathyroid hormone/parathyroid hormone-related peptides and vasoactive intestinal peptide receptors, all of which activate adenylyl cyclase and the phosphatidyl-inositol-calcium pathway. These receptors have 7 transmembrane helices, like rhodopsin-like GPCRs. However,there is no significant sequence identity between these families: the secretin-like receptors thus bear their own unique ‘7TM’ signature.

Subfamily B1

Subfamily B1 contains classical hormone receptors, such as receptors for secretin and glucagon, that are all involved in cAMP-mediated signalling pathways.

Subfamily B2

Subfamily B2 contains receptors with long extracellular N-termini, such as the leukocyte cell-surface antigen CD97; calcium-independent receptors for latrotoxin (such as O94910, and brain-specific angiogenesis inhibitor receptors (such as O14514) amongst others.

Brain-specific angiogenesis inhibitor InterPro: IPR008077
- BAI1; BAI2; BAI3
CD97 antigen InterPro: IPR003056
- CD97
EMR hormone receptor InterPro: IPR001740
- CELSR1; CELSR2; CELSR3; EMR1; EMR2; EMR3; EMR4
Gastric inhibitory polypeptide receptor InterPro: IPR001749
- GCGR; GIPR
GPR56 orphan receptor InterPro: IPR003910
- GPR56; GPR64; GPR97; GPR110; GPR111; GPR112; GPR113; GPR114; GPR115; GPR123; GPR125; GPR126; GPR128; GPR133; GPR144; GPR157
Latrophilin receptor InterPro: IPR003924
- ELTD1; LPHN1; LPHN2; LPHN3

Subfamily B3

Subfamily B3 includes Methuselah and other Drosophila proteins. Other than the typical seven-transmembrane region, characteristic structural features include an amino-terminal extracellular domain involved in ligand binding, and an intracellular loop (IC3) required for specific G-protein coupling.

Diuretic hormone receptor InterPro: IPR002001

Unclassified subfamilies

Ig-hepta receptor InterPro: IPR008078
- GPR116

Unclassified members

DREG; HCTR-5; HCTR-6; KPG_003; KPG_006; KPG_008; KPG_009; RESDA1

References

↑ Harmar AJ (2001). “Family-B G-protein-coupled receptors”. Genome Biol. 2 (12): REVIEWS3013. doi:10.1186/gb-2001-2-12-reviews3013. PMID 11790261.

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[pmid11790261-1] Harmar AJ (2001). “Family-B G-protein-coupled receptors”. Genome Biol. 2 (12): REVIEWS3013. doi:10.1186/gb-2001-2-12-reviews3013. PMID 11790261.

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