The GPS motif is found in GPCRs, and is the site for auto-proteolysis, so is thus named, GPS [1-4]. The GPS motif is a conserved sequence of ~40 amino acids containing canonical cysteine and tryptophan residues, and is the most highly conserved part ...
The GPS motif is found in GPCRs, and is the site for auto-proteolysis, so is thus named, GPS [1-4]. The GPS motif is a conserved sequence of ~40 amino acids containing canonical cysteine and tryptophan residues, and is the most highly conserved part of the domain. In most, if not all, cell-adhesion GPCRs these undergo autoproteolysis in the GPS between a conserved aliphatic residue (usually a leucine) and a threonine, serine, or cysteine residue [5]. In higher eukaryotes this motif is found embedded in the C-terminal beta-stranded part of a GAIN domain - GPCR-Autoproteolysis INducing (GAIN), described as subdomain B, The GAIN-GPS domain/subdomain B adopts a fold in which the GPS motif, at the C-terminus, forms five beta-strands that, together with subdomain A, forms the overall GAIN domain [7]. The GPS motif, evolutionarily conserved from tetrahymena to mammals, is the only extracellular domain shared by all human cell-adhesion GPCRs and PKD proteins, and is the locus of multiple human disease mutations. The GAIN-GPS domain is both necessary and sufficient functionally for autoproteolysis, suggesting an autoproteolytic mechanism whereby the overall GAIN domain fine-tunes the chemical environment in the GPS to catalyse peptide bond hydrolysis [6]. In the cell-adhesion GPCRs and PKD proteins, the GPS motif is always located at the end of their long N-terminal extracellular regions, immediately before the first transmembrane helix of the respective protein.
This family is known as Family B, the secretin-receptor family or family 2 of the G-protein-coupled receptors (GCPRs). They have been described in many animal species, but not in plants, fungi or prokaryotes. Three distinct sub-families are recognise ...
This family is known as Family B, the secretin-receptor family or family 2 of the G-protein-coupled receptors (GCPRs). They have been described in many animal species, but not in plants, fungi or prokaryotes. Three distinct sub-families are recognised. Subfamily B1 contains classical hormone receptors, such as receptors for secretin and glucagon, that are all involved in cAMP-mediated signalling pathways. Subfamily B2 contains receptors with long extracellular N-termini, such as the leukocyte cell-surface antigen CD97 (Swiss:P48960); calcium-independent receptors for latrotoxin (such as Swiss:O94910), and brain-specific angiogenesis inhibitors (such as Swiss:O14514) amongst others. Subfamily B3 includes Methuselah and other Drosophila proteins (e.g. Swiss:P83119). 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 [1].
