Signaling at zero G: G-protein-independent functions for 7-TM receptors.
Eukaryotic cells, whether free-living, single-celled microbes or components of complex metazoa, can sense environmental cues through specialized seven-transmembrane (7-TM) receptors (also called heptahelical or G-protein-coupled receptors). 7-TM receptors detect "inputs" such as light, peptide hormones, neurotransmitters, pheromones, odorants, morphogens and chemoattractants, linking extracellular stimuli to intracellular signaling networks via heterotrimeric G proteins. Recently, this obligatory paradigm has been challenged. A growing body of evidence indicates that 7-TM receptors can also transmit extracellular signals through mechanisms that function independently of G-protein coupling. This review discusses pathways and protein interactions for 7-TM receptors signaling "at zero G" in Dictyostelium and mammalian cells.
Brzostowski
J A
JA
Molecular Mechanisms of Development, Laboratory of Cellular and Developmental Biology, NIDDK/NIH, Bethesda, MD 20892-2715, USA.
Kimmel
A R
AR
D000818:Animals; D002462:Cell Membrane / Q000378:metabolism*; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism; D004023:Dictyostelium / Q000378:metabolism; D004789:Enzyme Activation; D005057:Eukaryotic Cells / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism*; D008954:Models, Biological; D010766:Phosphorylation; D017434:Protein Structure, Tertiary; D015398:Signal Transduction
D008565:Membrane Proteins; D000242:Cyclic AMP; D019204:GTP-Binding Proteins