Secretin receptor family
Protein family
From Wikipedia, the free encyclopedia
Secretin receptor family (class B GPCR subfamily[1]) consists of secretin receptors regulated by peptide hormones from the glucagon hormone family. The family is different from adhesion G protein-coupled receptors.[2]
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 seven transmembrane helices,[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 characteristic 7TM signature.[5]
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.[6] Three distinct sub-families (B1-B3) are recognized.
Subfamily B1
Subfamily B1 contains classical hormone receptors, such as receptors for secretin and glucagon, that are all involved in cAMP-mediated signalling pathways.
- Pituitary adenylate cyclase-activating polypeptide type 1 receptor InterPro: IPR002285
- Calcitonin receptor InterPro: IPR003287
- Calcitonin receptor-like receptor InterPro: IPR015476
- 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
Subfamily B2 contains receptors with long extracellular N-termini, such as the leukocyte cell-surface antigen CD97; calcium-independent receptors for latrotoxin[7] and brain-specific angiogenesis inhibitor receptors[8] 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
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.
Unclassified members
HCTR-5; HCTR-6; KPG 006; KPG 008