|PROSITE documentation PDOC00559 [for PROSITE entry PS50261]|
A number of peptide hormones bind to G-protein coupled receptors that, while structurally similar to family 1 of G-protein coupled receptors (R7G) (see <PDOC00210>), do not show any similarity at the level of their sequence, thus representing a new family whose current known members [1,2] are listed below:
In addition to the above characterized receptors, this family also includes:
All the characterized receptors are coupled to G-proteins which activate both adenylyl cyclase and the phosphatidylinositol-calcium pathway.
Like family 1 R7G they seem to contain seven transmembrane regions. Their N-terminus is probably located on the extracellular side of the membrane and potentially glycosylated, while their C-terminus 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.
Family two G protein coupled receptors contain a long conserved region in their N terminal extracellular part 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 disulfide bonds; we have developed a pattern in the region that spans the first three cysteines. We also developed a profile that covers the whole extracellular domain.
One of the most highly conserved regions spans the C-terminal part of the last transmembrane region and the beginning of the adjacent intracellular region. We have used this region as a second signature pattern. We also developed a profile that spans the seven transmembrane regions.Expert(s) to contact by email:
December 2004 / Pattern and text revised.
PROSITE methods (with tools and information) covered by this documentation:
|1||Authors||Jueppner H., Abou-Samra A.-B., Freeman M., Kong X.-F., Schipani E., Richards J., Kolakowski L.F. Jr., Hock J., Potts J.T. Jr., Kronenberg H.M., Segre G.V.|
|2||Authors||Hamann J., Hartmann E., van Lier R.A.W.|
|Title||Structure of the human CD97 gene: exon shuffling has generated a new type of seven-span transmembrane molecule related to the secretin receptor superfamily.|
|3||Authors||Bockaert J., Pin J.P.|
|Title||Molecular tinkering of G protein-coupled receptors: an evolutionary success.|
|Source||EMBO J. 18:1723-1729(1999).|