The goal of this project is to use new advances in cryo-electron microscopy (cryo-EM) technology to elucidate the structures of, at high-resolution, a range of functional states of ionotropic glutamate receptor (iGluR) ion channels, and to use complementary functional and biochemical assays to validate our findings and hypotheses driven by our solved cryo-EM models. iGluRs are responsible for the majority of excitatory neurotransmission, and are implicated in a wide range of pathologies, from neurodegenerative diseases and psychiatric disorders, to epilepsy and stroke-induced trauma. Current design of therapeutics targeting the range of iGluR functional states that dictate these different disease states is hindered by a lack of information describing iGluRs outside of a closed-channel state. This research will directly address the need for new views into these functional states by using cryo-EM based methods, which will allow crystallographic barriers in analyzing iGluR states to be overcome. Using state-of-the-art cryo-EM techniques, high-resolution cryo-EM of iGluRs will be established. With fluorescence-based construct screening strategies, new targets for isolating separate structural states in iGluR function will be identified. Namely, how auxiliary proteins interact with/regulate iGluRs and iGluR gating will be targeted. After cryo-EM analysis, data will be probed using advanced electrophysiological techniques and biochemical interrogation. The methods used in this project will serve as a foundation for investigating functional states across ion channel families, and may provide a much-needed template for structure-based drug design of new molecules targeting iGluR states.

Public Health Relevance

The proposed research targets the elucidation of three-dimensional structures of various functional states in a group of ion channels called ionotropic glutamate receptors (iGluRs). These structures will provide highly detailed information to help better understand how iGluRs function across various disease-related states, such as in neurodegenerative diseases and psychiatric disorders. The outcomes of this project will provide a foundation, from a structural biology perspective, for novel design of therapeutics targeting an array of iGluR functional states across neurological disorders.

National Institute of Health (NIH)
National Institute of Neurological Disorders and Stroke (NINDS)
Predoctoral Individual National Research Service Award (F31)
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Special Emphasis Panel (ZRG1)
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Silberberg, Shai D
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Columbia University (N.Y.)
Schools of Medicine
New York
United States
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Twomey, Edward C; Sobolevsky, Alexander I (2018) Structural Mechanisms of Gating in Ionotropic Glutamate Receptors. Biochemistry 57:267-276
Twomey, Edward C; Yelshanskaya, Maria V; Vassilevski, Alexander A et al. (2018) Mechanisms of Channel Block in Calcium-Permeable AMPA Receptors. Neuron 99:956-968.e4
McGoldrick, Luke L; Singh, Appu K; Saotome, Kei et al. (2018) Opening of the human epithelial calcium channel TRPV6. Nature 553:233-237
Singh, Appu K; McGoldrick, Luke L; Twomey, Edward C et al. (2018) Mechanism of calmodulin inactivation of the calcium-selective TRP channel TRPV6. Sci Adv 4:eaau6088
Twomey, Edward C; Yelshanskaya, Maria V; Grassucci, Robert A et al. (2017) Structural Bases of Desensitization in AMPA Receptor-Auxiliary Subunit Complexes. Neuron 94:569-580.e5
Twomey, Edward C; Yelshanskaya, Maria V; Grassucci, Robert A et al. (2017) Channel opening and gating mechanism in AMPA-subtype glutamate receptors. Nature 549:60-65
Twomey, Edward C; Yelshanskaya, Maria V; Grassucci, Robert A et al. (2016) Elucidation of AMPA receptor-stargazin complexes by cryo-electron microscopy. Science 353:83-6