GLUTAMATE-GATED CHANNELS IN CENTRAL &PERIPHERAL NEURONS

Summary

Principal Investigator: James E Huettner
Abstract: DESCRIPTION (provided by applicant): The long-term objective of my work is to provide a better understanding of synaptic transmission by studying the operation of NMDA, AMPA and kainate receptors, which form ion channels gated by the neurotransmitter glutamate. Another major goal is to uncover properties of these receptors that may allow for clinical intervention to prevent excitotoxic cell death or to provide analgesia. The experiments in this proposal arise from several interesting discoveries that we made during the current period of support. Specific Aim 1 follows up on our observation that interactions between the pore loop and adjacent transmembrane helices govern kainate receptor susceptibility to inhibition by cis-unsaturated fatty acids, such as docosahexaenoic acid (DHA). Experiments in this aim will use mutant cycle analysis to determine which residues in the channel interact with each other to control permeation, gating and modulation. Specific Aim 2 builds on our discovery that exposure to DHA appears to change the conformation of kainate receptor transmembrane helices in the open state. Reactivity of substituted cysteines, metal ion binding, and disulfide bond formation will be used to determine structural changes introduced by fatty acids. Specific Aim 3 follows up on our discovery of small molecule antagonists that prevent DHA from potentiating NMDA receptors but have little or no effect on DHA inhibition of kainate receptors. Chimeric subunits that combine domains from NMDA and kainate receptors will be used to investigate whether distinct structural interactions underlie the potentiation and inhibition of channel activity and t analyze the structural requirements for generation of functional channels. Collectively, these experiments will provide new information about the structural basis for ionotropic glutamate receptor operation and new information about how ion channels are affected by interactions with components of the lipid bilayer. A number of pathologic conditions, including brain trauma, epilepsy, and ischemia, elicit massive release of cis-unsaturated fatty acids. These compounds directly regulate many different membrane proteins including a number of ion channel subtypes. This project analyzes the molecular basis of glutamate receptor modulation by DHA, which is present at high levels in the nervous system and is known to be essential for normal brain function.
Funding Period: 1992-07-01 - 2017-04-30
more information: NIH RePORT

Top Publications

  1. ncbi R7BP augments the function of RGS7*Gbeta5 complexes by a plasma membrane-targeting mechanism
    Ryan M Drenan
    Department of Cell Biology and Physiology, Washington University School of Medicine, St Louis, Missouri 63110, USA
    J Biol Chem 281:28222-31. 2006
  2. pmc Radial symmetry in a chimeric glutamate receptor pore
    Timothy J Wilding
    Department of Cell Biology and Physiology, Washington University School of Medicine, 660 South Euclid Avenue, St Louis, Missouri 63110, USA
    Nat Commun 5:3349. 2014
  3. pmc Myosin II regulates activity dependent compensatory endocytosis at central synapses
    Indra Chandrasekar
    Departments of Anatomy and Neurobiology and Cell Biology and Physiology, Washington University School of Medicine, St Louis, Missouri 63110, and Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138
    J Neurosci 33:16131-45. 2013
  4. pmc Q/R site interactions with the M3 helix in GluK2 kainate receptor channels revealed by thermodynamic mutant cycles
    Melany N Lopez
    Department of Cell Biology and Physiology, Washington University School of Medicine in St Louis, St Louis, MO 63110, USA
    J Gen Physiol 142:225-39. 2013
  5. pmc An N-terminal polybasic domain and cell surface localization are required for mutant prion protein toxicity
    Isaac H Solomon
    Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118, USA
    J Biol Chem 286:14724-36. 2011
  6. pmc Fatty acid modulation and polyamine block of GluK2 kainate receptors analyzed by scanning mutagenesis
    Timothy J Wilding
    Department of Cell Biology and Physiology, Washington University Medical School, St Louis, MO 63110, USA
    J Gen Physiol 136:339-52. 2010
  7. pmc Neurotoxic mutants of the prion protein induce spontaneous ionic currents in cultured cells
    Isaac H Solomon
    Department of Cell Biology and Physiology, Washington University School of Medicine, St Louis, Missouri 63110, USA
    J Biol Chem 285:26719-26. 2010
  8. pmc Intrinsic, nondeterministic circadian rhythm generation in identified mammalian neurons
    Alexis B Webb
    Department of Biology, Washington University, St Louis, MO 63130, USA
    Proc Natl Acad Sci U S A 106:16493-8. 2009
  9. pmc Regulation of mouse embryonic stem cell neural differentiation by retinoic acid
    Mijeong Kim
    Department of Cell Biology and Physiology, Washington University Medical School, 660 South Euclid Avenue, St Louis, MO 63110, USA
    Dev Biol 328:456-71. 2009
  10. pmc The BTB/kelch protein, KRIP6, modulates the interaction of PICK1 with GluR6 kainate receptors
    Fernanda Laezza
    Department of Cell Biology and Physiology, Washington University, St Louis, MO 63110, USA
    Neuropharmacology 55:1131-9. 2008

Detail Information

Publications14

  1. ncbi R7BP augments the function of RGS7*Gbeta5 complexes by a plasma membrane-targeting mechanism
    Ryan M Drenan
    Department of Cell Biology and Physiology, Washington University School of Medicine, St Louis, Missouri 63110, USA
    J Biol Chem 281:28222-31. 2006
    ..Therefore, R7BP augments the function of the complex by a palmitoylation-regulated plasma membrane-targeting mechanism...
  2. pmc Radial symmetry in a chimeric glutamate receptor pore
    Timothy J Wilding
    Department of Cell Biology and Physiology, Washington University School of Medicine, 660 South Euclid Avenue, St Louis, Missouri 63110, USA
    Nat Commun 5:3349. 2014
    ..Our results indicate that Q/R site interaction with M3 occurs within individual subunits and is essentially the same for both A/C and B/D subunit conformations, suggesting that fourfold pore symmetry persists in the open state. ..
  3. pmc Myosin II regulates activity dependent compensatory endocytosis at central synapses
    Indra Chandrasekar
    Departments of Anatomy and Neurobiology and Cell Biology and Physiology, Washington University School of Medicine, St Louis, Missouri 63110, and Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138
    J Neurosci 33:16131-45. 2013
    ..Changes in retrieval rates determine the size of the recycling pool. The resulting effect on release rates, in turn, brings about changes in synaptic strength. ..
  4. pmc Q/R site interactions with the M3 helix in GluK2 kainate receptor channels revealed by thermodynamic mutant cycles
    Melany N Lopez
    Department of Cell Biology and Physiology, Washington University School of Medicine in St Louis, St Louis, MO 63110, USA
    J Gen Physiol 142:225-39. 2013
    ....
  5. pmc An N-terminal polybasic domain and cell surface localization are required for mutant prion protein toxicity
    Isaac H Solomon
    Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118, USA
    J Biol Chem 286:14724-36. 2011
    ..The sequence domains identified in our study are also critical for PrP(Sc) formation, suggesting that common structural features may govern both the functional activity of PrP(C) and its conversion to PrP(Sc)...
  6. pmc Fatty acid modulation and polyamine block of GluK2 kainate receptors analyzed by scanning mutagenesis
    Timothy J Wilding
    Department of Cell Biology and Physiology, Washington University Medical School, St Louis, MO 63110, USA
    J Gen Physiol 136:339-52. 2010
    ....
  7. pmc Neurotoxic mutants of the prion protein induce spontaneous ionic currents in cultured cells
    Isaac H Solomon
    Department of Cell Biology and Physiology, Washington University School of Medicine, St Louis, Missouri 63110, USA
    J Biol Chem 285:26719-26. 2010
    ..Drugs that block PrP-associated channels or pores may therefore represent novel therapeutic agents for treatment of patients with prion diseases...
  8. pmc Intrinsic, nondeterministic circadian rhythm generation in identified mammalian neurons
    Alexis B Webb
    Department of Biology, Washington University, St Louis, MO 63130, USA
    Proc Natl Acad Sci U S A 106:16493-8. 2009
    ..Instead, these results indicate that AVP, VIP, and other SCN neurons are intrinsic but unstable circadian oscillators that rely on network interactions to stabilize their otherwise noisy cycling...
  9. pmc Regulation of mouse embryonic stem cell neural differentiation by retinoic acid
    Mijeong Kim
    Department of Cell Biology and Physiology, Washington University Medical School, 660 South Euclid Avenue, St Louis, MO 63110, USA
    Dev Biol 328:456-71. 2009
    ..Transcriptional profiling indicates a substantial representation of transit amplifying neuroblasts in SFD cultures not exposed to RA...
  10. pmc The BTB/kelch protein, KRIP6, modulates the interaction of PICK1 with GluR6 kainate receptors
    Fernanda Laezza
    Department of Cell Biology and Physiology, Washington University, St Louis, MO 63110, USA
    Neuropharmacology 55:1131-9. 2008
    ....
  11. pmc Amino acid substitutions in the pore helix of GluR6 control inhibition by membrane fatty acids
    Timothy J Wilding
    Department of Cell Biology and Physiology, Washington University Medical School, St Louis, MO 63110, USA
    J Gen Physiol 132:85-99. 2008
    ..Based on homology with the pore loop of potassium channels, locations at which R substitution induces susceptibility to fatty acid inhibition face away from the cytoplasm toward the M1 and M3 helices and surrounding lipids...
  12. pmc KRIP6: a novel BTB/kelch protein regulating function of kainate receptors
    Fernanda Laezza
    Department of Anatomy and Neurobiology, Washington University School of Medicine, St Louis, MO 63110, USA
    Mol Cell Neurosci 34:539-50. 2007
    ..Taken together, these results suggest that KRIP6 can directly regulate native kainate receptors and provide the first evidence for a BTB/kelch protein in direct functional regulation of a mammalian glutamate receptor...
  13. pmc GABA and Gi/o differentially control circadian rhythms and synchrony in clock neurons
    Sara J Aton
    Department of Biology, Washington University, St Louis, MO 63130, USA
    Proc Natl Acad Sci U S A 103:19188-93. 2006
    ..We propose that G(i/o), not GABA activity, converges with VIP signaling to maintain and coordinate rhythms among SCN neurons...

Research Grants30

  1. Mechanism for Regulating Kainate-Type Glutamate Receptor Activity
    Susumu Tomita; Fiscal Year: 2013
    ..Because potential roles of kainate receptors in several neurological diseases including autism, schizophrenia, epilepsy and altered sensory transduction have been proposed, this work will identify novel targets for drug discovery. ..
  2. The Functional Significance of Conformational States in Glutamatergic Signaling
    CATHERINE LOURDES SALUSSOLIA; Fiscal Year: 2013
    ..Thus, by defining novel aspects of glutamate receptor structure-function my studies will serve to further understand glutamate receptor gating and may lead to novel strategies to treat glutamate-based neurological diseases. ..
  3. Structural biology of neurotransmitter ion channels
    James E Gouaux; Fiscal Year: 2013
    ....
  4. Structure and Function of NMDA Receptors
    Hiroyasu Furukawa; Fiscal Year: 2013
    ..Defining the molecular structure of the extracellular region of NMDA receptors is expected to help in the design of new therapeutics. ..
  5. Molecular Mechanisms linking Aging, Abeta Proteotoxicity and Neurodegeneration
    Jeffery W Kelly; Fiscal Year: 2013
    ..abstract_text> ..
  6. Optimization of small molecule probes
    Stephen F Traynelis; Fiscal Year: 2013
    ..We will evaluate plasma half-life, brain:plasma ratio, and neurotoxicity in vitro. ..
  7. Alerations of Sleep and Circadian Timing in Aging
    Eve Van Cauter; Fiscal Year: 2013
    ..Core B (Methods and Analysis) will standard operating procedures for data collection, archival and analysis. Core C will assay peripheral levels of hormones, cytokines and other blood constituents. ..
  8. A Gene therapeutic approach to stable suppression of HIV-1 replication
    MICHAEL R FARZAN; Fiscal Year: 2013
    ..These studies will establish principles and protocols directly applicable to subsequent human clinical trials. ..
  9. Discovery, Design, and Development of Phosphonic Acid Antibiotics
    William W Metcalf; Fiscal Year: 2013
    ..The entire project will be housed in the new Institute for Genomic Biology at the University of Illinois, where the program project team occupies a single, large contiguous, laboratory. ..
  10. DGAP: Developmental Genome Anatomy Project
    CYNTHIA CASSON MORTON; Fiscal Year: 2013
    ....
  11. Regional, Synpatic, Cellular Modulation of Abeta Metabolism
    David M Holtzman; Fiscal Year: 2013
    ..abstract_text> ..