A brief review on the evolution of GPCR: conservation and diversification

G-protein couple receptors (GPCR) possess diversified functions and they comprise a large protein superfamily in cellular signaling. Numerous identification methods for GPCR have been employed and versatile GPCR types are discussed. Although they share conserved transmembrane structural topology, alignment results of all GPCR show no significant sequence similarities. Each GPCR type distributes diversely in different evolutionary hierarchies of eukaryotes, but it has a distinctive boundary in the era of metazoan. The common ancestor of GPCR metabotropic glutamate receptor includes 7-transmembrane structure and venus flytrap module, which is probably evolved from a compound of bacteriorhodopsin and periplasmic binding protein. Many investigations focus on fine structure shaping and GPCR classification. Here, we briefly discuss evolutionary dynamic mechanism of GPCR from the perspective of classification, diversification and conservation.