Using green fluorescent proteins to stud G-protein-coupled receptor localization and trafficking

G-protein-coupled receptors (GPCRs) mediate a diverse array of biological f unctions as a result of their ability to respond selectively to extra cellu lar stimuli, which ultimately results in cell-specific activation of signal ing cascades. Generally, GPCR activation is followed rapidly by a loss of r esponsiveness, termed desensitization, which is then followed by a period o f recovery or resensitization, These changes in signaling potential are tig htly regulated, primarily via mechanisms that involve GPCR phosphorylation and trafficking to distinct locations within the cell. Tagging of GPCRs wit h the green fluorescent protein (GFP) has enabled the direct visualization of real-time trafficking of GPCRs in living cells. Such analyses have provi ded crucial insight into the mechanisms involved in controlling GPCR functi on.