R7BP: a surprising new link between G proteins, RGS proteins, and nuclear signaling in the brain.
The regulators of G protein signaling (RGS proteins) bind directly to G protein alpha (Galpha) subunits in brain and other tissues to determine the strength, duration, and fidelity of neurotransmitter receptor signaling. A recent study shows, quite unexpectedly, that one class of RGS proteins [the R7 subfamily bound to Gbeta(5) (R7-Gbeta(5))] shuttles between the plasma membrane and the nucleus with assistance from a novel shuttle protein, R7BP. R7BP binds directly to R7-Gbeta(5) and the protein complex is tethered to the plasma membrane by addition of a lipid, palmitate, on R7BP. Removal of palmitate results in the translocation of the R7BP-R7-Gbeta(5) complex to the nucleus, presumably for nontraditional signaling functions. These findings suggest an entirely novel mechanism for regulating neurotransmitter signaling. That is, R7BP transduces signals directly from receptors and G proteins at the plasma membrane to the nucleus, and this plasma membrane-nuclear shuttling is controlled by reversible palmitoylation of R7BP.
Hepler
John R
JR
Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322-3090, USA. jhepler@emory.edu
D000818:Animals; D001921:Brain / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D002467:Cell Nucleus / Q000502:physiology*; D003600:Cytosol / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000502:physiology*; D005786:Gene Expression Regulation; D006801:Humans; D008954:Models, Biological; D005810:Multigene Family; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000502:physiology*; D019308:Palmitic Acid / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D021122:Protein Subunits; D021381:Protein Transport; D020710:RGS Proteins / Q000737:chemistry / Q000145:classification / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*; D012995:Solubility; D014158:Transcription, Genetic
D009419:Nerve Tissue Proteins; D021122:Protein Subunits; C499440:R7BP protein, mouse; D020710:RGS Proteins; D019308:Palmitic Acid; D019204:GTP-Binding Proteins