Secretin receptor family
|Secretin family of 7 transmembrane receptors|
Secretin family receptor proteins, also known as Family B or family 2 of G-protein coupled receptors are regulated by peptide hormones from the glucagon hormone family. The family is different from adhesion G protein-coupled receptors.
The secretin-receptor family of GPCRs include vasoactive intestinal peptide receptors and receptors for secretin, calcitonin and parathyroid hormone/parathyroid hormone-related peptides. These receptors activate adenylyl cyclase and the phosphatidyl-inositol-calcium pathway. The receptors in this family have 7 transmembrane helices, like rhodopsin-like GPCRs. However, there is no significant sequence identity between these two GPCR families and the secretin-receptor family has its own characteristic 7TM signature.
The secretin-receptor family GPCRs exist in many animal species. Data mining with the Pfam signature has identified members in fungi, although due to their presumed non-hormonal function they are more commonly referred to as Adhesion G protein-coupled receptors, making the Adhesion subfamily the more basal group. Three distinct sub-families (B1-B3) are recognized.
- Pituitary adenylate cyclase-activating polypeptide type 1 receptor InterPro: IPR002285
- Calcitonin receptor InterPro: IPR003287
- Corticotropin-releasing hormone receptor InterPro: IPR003051
- Glucose-dependent insulinotropic polypeptide receptor/Gastric inhibitory polypeptide receptor InterPro: IPR001749
- Glucagon receptor InterPro: IPR003291
- Glucagon receptor-related InterPro: IPR003290
- Growth hormone releasing hormone receptor InterPro: IPR003288
- Parathyroid hormone receptor InterPro: IPR002170
- Secretin receptor InterPro: IPR002144
- Vasoactive intestinal peptide receptor InterPro: IPR001571
Subfamily B2 contains receptors with long extracellular N-termini, such as the leukocyte cell-surface antigen CD97; calcium-independent receptors for latrotoxin and brain-specific angiogenesis inhibitor receptors amongst others. They are otherwise known as Adhesion G protein-coupled receptors.
- Brain-specific angiogenesis inhibitor InterPro: IPR008077
- CD97 antigen InterPro: IPR003056
- EMR hormone receptor InterPro: IPR001740
- GPR56 orphan receptor InterPro: IPR003910
- Latrophilin receptor InterPro: IPR003924
- Ig-hepta receptor InterPro: IPR008078
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.
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- Bibcode:2017Natur.546..312S. doi:10.1038/nature22378. PMID 28514449. ; Song G, Yang D, Wang Y, de Graaf C, Zhou Q, Jiang S, et al. (June 2017). "Human GLP-1 receptor transmembrane domain structure in complex with allosteric modulators". Nature. 546 (7657): 312–315.
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