Receptor-Mediated Activation of Heterotrimeric G-Proteins in Living Cells

摘要: Receptor-mediated activation of heterotrimeric GTP-binding proteins (G-proteins) was visualized in living Dictyostelium discoideum cells by monitoring fluorescence resonance energy transfer (FRET) between alpha- and beta- subunits fused to cyan yellow fluorescent proteins. The G-protein heterotrimer rapidly dissociated reassociated upon addition removal chemoattractant. During continuous stimulation, reached a dose-dependent steady-state level. Even though physiological responses subsided, the did not decline. Thus, adaptation occurs at another point signaling pathway, occupied receptors, whether or they are phosphorylated, catalyze cycle. Construction similar energy-transfer pairs mammalian G-proteins should enable direct situ mechanistic studies applications such as drug screening identifying ligands newly found G-protein-coupled receptors.