| Secretin family of 7 transmembrane receptors | |||||||
|---|---|---|---|---|---|---|---|
| Identifiers | |||||||
| Symbol | 7tm_2 | ||||||
| Pfam | PF00002 | ||||||
| InterPro | IPR000832 | ||||||
| PROSITE | PDOC00559 | ||||||
| TCDB | 9.A.14 | ||||||
| OPM superfamily | 6 | ||||||
| OPM protein | 4k5y | ||||||
| CDD | cd13952 | ||||||
| |||||||
Secretin receptor family (class BGPCR subfamily[1]) consists ofsecretin receptors regulated bypeptide hormones from theglucagon hormone family. The family is different fromadhesion G protein-coupled receptors.[2]
The secretin-receptor family of GPCRs includevasoactive intestinal peptide receptors and receptors forsecretin,calcitonin andparathyroid hormone/parathyroid hormone-related peptides. These receptors activateadenylyl cyclase and thephosphatidyl-inositol-calcium pathway. The receptors in this family have seventransmembranehelices,[3][4] like rhodopsin-like GPCRs. However, there is no significant sequence identity between these two GPCR families and the secretin-receptor family has its own characteristic7TM signature.[5]
The secretin-receptor family GPCRs exist in many animal species. Data mining with thePfam signature has identified members in fungi, although due to their presumed non-hormonal function they are more commonly referred to asAdhesion G protein-coupled receptors, making theAdhesion subfamily the more basal group.[6] Three distinct sub-families (B1-B3) are recognized.
Subfamily B1 contains classicalhormone receptors, such as receptors forsecretin andglucagon, that are all involved in cAMP-mediated signalling pathways.
Subfamily B2 contains receptors with long extracellular N-termini, such as the leukocyte cell-surface antigenCD97; calcium-independent receptors forlatrotoxin[7] andbrain-specific angiogenesis inhibitor receptors[8] amongst others. They are otherwise known asAdhesion G protein-coupled receptors.
Subfamily B3 includesMethuselah and otherDrosophila 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.