Presentation Abstract

Session Title: PLATFORM U: Membrane Receptors & Signal Transduction II
Location: Room 309
Presentation Number: 976-Plat
Presentation Time: 3/7/2011 8:15:00 AM
Abstract Title: DESIGN AND APPLICATION OF A LIGHT-ACTIVATED METABOTROPIC GLUTAMATE RECEPTOR FOR OPTICAL CONTROL OF INTRACELLULAR SIGNALING PATHWAYS
Author Block: Joshua Levitz1, Benjamin Gaub1, Harald Janovjak2, Philipp Stawski2, Dirk Trauner2, Ehud Y. Isacoff1.
1UC Berkeley, Berkeley, CA, USA, 2University of Munich, Munich, Germany.
Abstract Body: A LIGHT-ACTIVATED METABOTROPIC GLUTAMATE RECEPTOR FOR OPTICAL CONTROL OF INTRACELLULAR SIGNALING
The ability to manipulate ion channels with light via photoisomerizable tethered ligands (PTLs) has opened the door for the optical control of neural activity both in cultured cells and in vivo. We have extended this to G-protein-coupled receptors by making a light-activated metabotropic glutamate receptor (mGluR). Taking into account pharmacological, structural and computational data, we screened PTLs in the MAG (Maleimide-Azobenzene-Glutamate) family, which included previously synthesized L and newly synthesized D stereoisomers with variable linker lengths. These were tested at several different sites of cysteine introduction in the ligand binding domain of mGluR2. Photo-control was tested by patch clamp recordings of HEK293 cells expressing the cysteine-substituted mGluR2 along with a G-protein-coupled inward rectifier potassium channel (GIRK) as a reporter. We identified combinations of cysteine substitutions, MAG stereochemistry and linker length that worked as either a light-gated agonist or antagonist of mGluR2. Liganding was reversible, turned on by 380 nm light that photoisomerizes the azobenzene to cis and turned off by 500 nm light that photoisomerizes the azobenzene to trans. The efficacy and kinetics of photo-activation and antagonism approached those obtained with pharmacological agents. In cultured hippocampal neurons the light-activated mGluR2 activated GIRKs, and hence rapidly and reversibly suppressed excitability. In hippocampal autapses the light-activated mGluR2 inhibited both glutamatergic and GABAergic synaptic transmission and altered short-term plasticity with equal reversibility and speed. The ability to optically manipulate mGluRs provides an orthogonal, non-invasive approach to probe the role of intracellular signaling pathways in biological functions with high spatiotemporal precision. Future work aims to use these optogenetic tools to probe the spatiotemporal properties of mGluR-mediated forms of long-term plasticity in intact brain slices and in vivo.
Commercial Relationship:  J. Levitz: None. B. Gaub: None. H. Janovjak: None. P. Stawski: None. D. Trauner: None. E.Y. Isacoff: None.



Technical Support Help Desk
Phone: 217-398-1792
Email: Help Desk