Secretin receptor family
Secretin family of 7 transmembrane receptors
|Available PDB structures:|
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.
- Adenylate cyclase-activating type 1 receptor, pituitary InterPro IPR002285
- Calcitonin receptor InterPro IPR003287
- Corticotropin-releasing hormone receptor InterPro IPR003051
- 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 (such as UniProt O94910, and brain-specific angiogenesis inhibitor receptors (such as UniProt O14514) amongst others.
- Brain-specific angiogenesis inhibitor InterPro IPR008077
- CD97 antigen InterPro IPR003056
- EMR hormone receptor InterPro IPR001740
- Gastric inhibitory polypeptide receptor InterPro IPR001749
- GPR56 orphan receptor InterPro IPR003910
- Latrophilin receptor InterPro IPR003924
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.