G protein-coupled receptors (GPCRs), also known as seven-(pass)-transmembrane domain receptors, 7TM receptors, heptahelical receptors, serpentine receptors, and G protein-linked receptors (GPLR), form a large group of evolutionarily-related proteins that are cell surface receptors that detect molecules outside the cell and activate cellular responses. Coupling with G proteins, they are called seven-transmembrane receptors because they pass through the cell membrane seven times. Ligands can bind either to extracellular N-terminus and loops or to the binding site within transmembrane helices. They are all activated by agonists although a spontaneous auto-activation of an empty receptor can also be observed.
G proteins, also known as guanine nucleotide-binding proteins, are a family of proteins that act as molecular switches inside cells, and are involved in transmitting signals from a variety of stimuli outside a cell to its interior. Their activity is regulated by factors that control their ability to bind to and hydrolyze guanosine triphosphate (GTP) to guanosine diphosphate (GDP). When they are bound to GTP, they are 'on', and, when they are bound to GDP, they are 'off'. G proteins belong to the larger group of enzymes called GTPases.
The Wnt signaling pathways are a group of signal transduction pathways which begin with proteins that pass signals into a cell through cell surface receptors. The name Wnt is a portmanteau created from the names Wingless and Int-1. Wnt signaling pathways use either nearby cell-cell communication (paracrine) or same-cell communication (autocrine). They are highly evolutionarily conserved in animals, which means they are similar across animal species from fruit flies to humans.
Pleckstrin homology domain or (PHIP) is a protein domain of approximately 120 amino acids that occurs in a wide range of proteins involved in intracellular signaling or as constituents of the cytoskeleton.
Casein kinase 2 (CK2/CSNK2) is a serine/threonine-selective protein kinase that has been implicated in cell cycle control, DNA repair, regulation of the circadian rhythm, and other cellular processes. De-regulation of CK2 has been linked to tumorigenesis as a potential protection mechanism for mutated cells. Proper CK2 function is necessary for survival of cells as no knockout models have been successfully generated.
G-protein-coupled receptor kinase 2 (GRK2) is an enzyme that in humans is encoded by the ADRBK1 gene. GRK2 was initially called Beta-adrenergic receptor kinase, and is a member of the G protein-coupled receptor kinase subfamily of the Ser/Thr protein kinases that is most highly similar to GRK3(βARK2).
Axin-1 is a protein that in humans is encoded by the AXIN1 gene.
Regulators of G protein signaling (RGS) are protein structural domains or the proteins that contain these domains, that function to activate the GTPase activity of heterotrimeric G-protein α-subunits.
Segment polarity protein dishevelled homolog DVL-1 is a protein that in humans is encoded by the DVL1 gene.
GIPC PDZ domain containing family, member 1 (GIPC1) is a protein that in humans is encoded by the GIPC1 gene. GIPC was originally identified as it binds specifically to the C terminus of RGS-GAIP, a protein involved in the regulation of G protein signaling. GIPC is an acronym for "GAIP Interacting Protein C-terminus". RGS proteins are "Regulators of G protein Signaling" and RGS-GAIP is a "GTPase Activator protein for Gαi/Gαq", which are two major subtypes of Gα proteins. The human GIPC1 molecule is 333 amino acids or about 36 kDa in molecular size and consists of a central PDZ domain, a compact protein module which mediates specific protein-protein interactions. The RGS-GAIP protein interacts with this domain and many other proteins interact here or at other parts of the GIPC1 molecule. As a result, GIPC1 was independently discovered by several other groups and has a variety of alternate names, including synectin, C19orf3, RGS19IP1 and others. The GIPC1 gene family in mammals consisting of three members, so the first discovered, originally named GIPC, is now generally called GIPC1, with the other two being named GIPC2 and GIPC3. The three human proteins are about 60% identical in protein sequence. GIPC1 has been shown to interact with a variety of other receptor and cytoskeletal proteins including the GLUT1 receptor, ACTN1, KIF1B, MYO6, PLEKHG5, SDC4/syndecan-4, SEMA4C/semaphorin-4 and HTLV-I Tax. The general function of GIPC family proteins therefore appears to be mediating specific interactions between proteins involved in G protein signaling and membrane translocation.
Guanine nucleotide-binding protein subunit beta-5 is a protein that in humans is encoded by the GNB5 gene. Alternatively spliced transcript variants encoding different isoforms exist.
Regulator of G-protein signaling 7 is a protein that in humans is encoded by the RGS7 gene.
Regulator of G-protein signalling 9, also known as RGS9, is a human gene, which codes for a protein involved in regulation of signal transduction inside cells. Members of the RGS family, such as RGS9, are signaling proteins that suppress the activity of G proteins by promoting their deactivation.[supplied by OMIM]
Regulator of G-protein signaling 6 is a protein that in humans is encoded by the RGS6 gene.
Guanine nucleotide-binding protein G(k) subunit alpha is a protein that in humans is encoded by the GNAI3 gene.
Regulator of G-protein signaling 11 is a protein that in humans is encoded by the RGS11 gene.
Dishevelled (Dsh) is a family of proteins involved in canonical and non-canonical Wnt signalling pathways. Dsh is a cytoplasmic phosphoprotein that acts directly downstream of frizzled receptors. It takes its name from its initial discovery in flies, where a mutation in the dishevelled gene was observed to cause improper orientation of body and wing hairs. There are vertebrate homologs in zebrafish, Xenopus (Xdsh), mice and humans. Dsh relays complex Wnt signals in tissues and cells, in normal and abnormal contexts. It is thought to interact with the novel protein, SPATS1, when regulating the Wnt Signalling pathway.
GoLoco motif is a protein structural motif.
DEPDC5 is a human protein of poorly understood function but has been associated with cancer in several studies. It is encoded by a gene of the same name, located on chromosome 22.
