Pathways & interactions
GPCR family 2, Ig-hepta-like receptor (IPR008078)
Short name: GPCR_2_Ig-hepta-like_rcpt
Overlapping homologous superfamilies
- GPCR, family 2, secretin-like (IPR000832)
- GPCR family 2, Ig-hepta-like receptor (IPR008078)
Ig-Hepta/GPR116 is a member of the G protein-coupled receptor family. It has been named Ig-hepta due to the presence of two immunoglobulin-like repeats in its large extracellular domain. The receptor is expressed predominantly in the lung, this expression being strongly induce postnatally. Biochemical analysis indicates that Ig-hepta/GPR116 is heavily glycosylated and exists as a disulphide-linked dimer. The receptor appears to be localised in alveolar walls of the lungs and intercalated cells of the kidney collecting ducts, suggesting a role in regulation of acid-base balance [PMID: 10391944]. Ig-Hepta/GPR116 is likely to negatively regulate macrophage function and inflammation in the alveoli [PMID: 25778400].
This entry also includes GPR110 and GPR115. Loss of GPR110 and GPR115 function does not result in detectable defects, indicating that genes of this GPCR group might function redundantly [PMID: 22837050].
The secretin-like GPCRs include secretin [PMID: 1646711], calcitonin [PMID: 1658940], parathyroid hormone/parathyroid hormone-related peptides [PMID: 1658941] and vasoactive intestinal peptide [PMID: 1314625], all of which activate adenylyl cyclase and the phosphatidyl-inositol-calcium pathway. These receptors contain seven transmembrane regions, in a manner reminiscent of the rhodopsins and other receptors believed to interact with G-proteins (however there is no significant sequence identity between these families, the secretin-like receptors thus bear their own unique '7TM' signature). Their N terminus is probably located on the extracellular side of the membrane and potentially glycosylated. This N-terminal region contains a long conserved region which allow the binding of large peptidic ligand such as glucagon, secretin, VIP and PACAP; this region contains five conserved cysteines residues which could be involved in disulphide bond. The C-terminal region of these receptor is probably cytoplasmic. Every receptor gene in this family is encoded on multiple exons, and several of these genes are alternatively spliced to yield functionally distinct products.
- PR01695 (IGHEPTARCPTR)