Secretin receptor family

Secretin family of 7 transmembrane receptors
Identifiers
Symbol	7tm_2
Pfam	PF00002
InterPro	IPR000832
PROSITE	PDOC00559
SCOP	1bl1
SUPERFAMILY	1bl1
OPM superfamily	6
OPM protein	1fjr
Available protein structures: Pfam structures PDB RCSB PDB; PDBe; PDBj PDBsum structure summary

Secretin family of 7 transmembrane receptors is a family of evolutionarily related proteins.

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.

• Adenylate cyclase-activating type 1 receptor, pituitary InterPro: IPR002285
  • ADCYAP1R1
• Calcitonin receptor InterPro: IPR003287
  • CALCR; CALCRL
• Corticotropin-releasing hormone receptor InterPro: IPR003051
  • CRHR1; CRHR2
• Glucagon receptor-related InterPro: IPR003290
  • GLP1R; GLP2R; GPCR
• Growth hormone releasing hormone receptor InterPro: IPR003288
  • GHRHR
• Parathyroid hormone receptor InterPro: IPR002170
  • PTHR1; PTHR2
• Secretin receptor InterPro: IPR002144
  • SCTR
• Vasoactive intestinal peptide receptor InterPro: IPR001571
  • VIPR1; VIPR2

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