TY - JOUR TI - Probing the ionotropic activity of glutamate GluD2 receptor in HEK cells with genetically-engineered photopharmacology AU - Lemoine, Damien AU - Mondoloni, Sarah AU - Tange, Jérome AU - Lambolez, Bertrand AU - Faure, Philippe AU - Taly, Antoine AU - Tricoire, Ludovic AU - Mourot, Alexandre A2 - Maduke, Merritt A2 - Swartz, Kenton J A2 - Gantz, Stephanie C A2 - Wollmuth, Lonnie A2 - Koster, Anna VL - 9 PY - 2020 DA - 2020/10/28 SP - e59026 C1 - eLife 2020;9:e59026 DO - 10.7554/eLife.59026 UR - https://doi.org/10.7554/eLife.59026 AB - Glutamate delta (GluD) receptors belong to the ionotropic glutamate receptor family, yet they don’t bind glutamate and are considered orphan. Progress in defining the ion channel function of GluDs in neurons has been hindered by a lack of pharmacological tools. Here, we used a chemo-genetic approach to engineer specific and photo-reversible pharmacology in GluD2 receptor. We incorporated a cysteine mutation in the cavity located above the putative ion channel pore, for site-specific conjugation with a photoswitchable pore blocker. In the constitutively open GluD2 Lurcher mutant, current could be rapidly and reversibly decreased with light. We then transposed the cysteine mutation to the native receptor, to demonstrate with high pharmacological specificity that metabotropic glutamate receptor signaling triggers opening of GluD2. Our results assess the functional relevance of GluD2 ion channel and introduce an optogenetic tool that will provide a novel and powerful means for probing GluD2 ionotropic contribution to neuronal physiology. KW - optogenetics KW - photopharmacology KW - glutamate receptors KW - tethered ligands KW - ion channels KW - azobenzene JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -