G-Protein-Coupled Receptors and Effectors in Nervous System

Classification and Structure of GPCR

G protein-coupled receptors (GPCRs) are regulated by many agonists, but all share a characteristic core composed of seven transmembrane α-helices that weave in and out of the membrane.

Fig.1 Diversity of GPCR Structures from Different Classes. (Congreve, 2020)

GPCRs in Nervous System

GPCRs are metabotropic receptors that bind to their ligands and cause slow synaptic transmission. The rhodopsin or class A family of GPCRs has been recognized as the largest source of therapeutic targets. However, a large number of the rhodopsin-like receptors are named orphans and mostly have no known ligand(s). They may be the answer for some known drug effects or adverse drug reactions with unidentified mechanisms of action.

Fig.2 A schematic illustration of the orphan GPCRs in the CNS. (Alavi, 2018)

Mechanism

GPCRs can signal a wide range of cellular pathways. The binding of agonists results in a conformational change that leads to engagement with downstream signaling proteins, primarily heterotrimeric G proteins. Binding of the activated GPCR to the G protein results in the exchange of GDP for GTP and the dissociation of the G-protein subunits. The Gα and Gβγ subunits then activate downstream signaling pathways, resulting in the modification of intracellular levels of cAMP or calcium, activation or inhibition of ion channels, or activation of enzyme signaling cascades. Receptor signaling is terminated by a range of mechanisms, including dissociation of the ligand, phosphorylation of the receptor by specific GPCR kinases, binding of β-arrestin, and/or receptor internalization. It has been reported that some receptors may continue to signal once internalized.

Fig.3 Schematic illustration of GPCR signaling. (Wootten, 2018)

Creative Biolabs has developed a comprehensive neuro-based research platform that contains both neuro research-based products and relevant services to customers around the world. Every effort we made during years of practice is to provide our customers with better and more reliable service.

If you are interested in neuro products and relevant services or have any other requirements, please don’t hesitate to contact us for more information.

References

1. Congreve, M.; et al. Impact of GPCR structures on drug discovery. Cell. 2020, 181(1): 81-91.
2. Alavi, M. S.; et al. Orphan G protein-coupled receptors: The role in CNS disorders. Biomed Pharmacother. 2018, 98: 222-232.
3. Wootten, D.; et al. Mechanisms of signaling and biased agonism in G protein-coupled receptors. Nat Rev Mol Cell Biol. 2018, 19(10): 638-653.