Research project Regulation & Desensitization of Ligand-Gated Ion Channels
We seek to use this to determine the molecular mechanisms of the gating process, explain subtype-specific binding and modulation for human channels, and understand why channels spontaneously desensitize shortly after opening. In particular, we propose to use cryo-EM, molecular dynamics simulations, and neutron scattering to understand gating and regulation by pH and calcium for a new symbiote multi-domain channel (DeCLIC) that shares many properties with human channels. We will also use simulations and electrophysiology to quantify modulator binding in specific subtype interfaces of our recently reported cryo-EM structures of a human heteromeric GABA(A) receptor, and pursue a structure of a new GABA(A) subtype showing tissue-specific modulation by neurosteroids. Finally, we will use new acetylcholine receptor structures to describe the mechanism of the entire cycle through open-closed-desensitized states. This should advance our fundamental understanding of conformational transitions for a broad class of physiologically important ligand-gated channels, and particularly shed light on subtype-specific drug (side-)effects.