Orthogonal Optical Control of a G Protein-Coupled Receptor with a SNAP-Tethered Photochromic Ligand
journal contributionposted on 17.12.2015, 10:24 by Johannes Broichhagen, Arunas Damijonaitis, Joshua Levitz, Kevin R. Sokol, Philipp Leippe, David Konrad, Ehud Y. Isacoff, Dirk Trauner
The covalent attachment of synthetic photoswitches is a general approach to impart light sensitivity onto native receptors. It mimics the logic of natural photoreceptors and significantly expands the reach of optogenetics. Here we describe a novel photoswitch designthe photoswitchable orthogonal remotely tethered ligand (PORTL)that combines the genetically encoded SNAP-tag with photochromic ligands connected to a benzylguanine via a long flexible linker. We use the method to convert the G protein-coupled receptor mGluR2, a metabotropic glutamate receptor, into a photoreceptor (SNAG-mGluR2) that provides efficient optical control over the neuronal functions of mGluR2: presynaptic inhibition and control of excitability. The PORTL approach enables multiplexed optical control of different native receptors using distinct bioconjugation methods. It should be broadly applicable since SNAP-tags have proven to be reliable, many SNAP-tagged receptors are already available, and photochromic ligands on a long leash are readily designed and synthesized.