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Principal Investigator: William Dylan Hale
Organization: JOHNS HOPKINS UNIVERSITY
Fiscal Year: 2024
Award: $102,973
Funding agency: National Institute of Mental Health
PROJECT SUMMARY
AMPA-type glutamate receptors (AMPARs) are the major excitatory neurotransmitter receptors in the
brain and changes in AMPAR number at synapses underlie learning and memory as well as human disease. A
detailed understanding of how AMPARs are organized at synapses is critical to understand how synaptic
strength is regulated and for the development of therapeutics to correct circuit imbalances in human disease.
The long-term goal of this proposal is to use Cryo-EM to understand how the structural basis of AMPAR
N-terminal domain interactions (NTDs) drive functional outcomes such as increased AMPAR accumulation and
synaptic strength. The rationale for this approach is twofold 1) it will help resolve long-standing questions about
the regulation of key neurotransmitter receptors; and 2) a detailed structural model of AMPARs participating in
key regulatory complexes will guide future therapeutic approaches that seek to alter the strength of excitatory
input onto neurons implicated in psychiatric illnesses like schizophrenia. The adhesion protein NPTX2 binds to
AMPARs, clusters AMPARs at synapses, and is required for homeostatic scaling of interneuron-specific GluA4-
containing AMPARs. Therefore, NPTX2-dependent GluA4 scaling is an ideal model for testing the hypothesis
that direct extracellular interactions with AMPARs control synaptic strength. This approach is innovative because
models of AMPAR plasticity have never been observed in structural detail. This research is significant because
it will yield new insights into how AMPAR interactions drive plasticity and how this can be exploited for therapeutic
benefit in the future. An example of such an approach would be a structure-guided therapeutic strategy for
clustering GluA4 on the surface of Parvalbumin-expressing interneurons (PVINs), which exhibit lowered
excitatory drive in models of schizophrenia.
The long-term goal of this project will be achieved with the following two specific aims: 1) Determine the
structure of the NPTX2/GluA4 complex via single particle Cryo-EM. and 2) Test whether NPTX2 drives
GluA4 PVIN scaling through a direct interaction. For the first aim we will employ single-particle Cryo-EM to
solve the structure of the activity-regulated synaptic adhesion molecule NPTX2 in complex with the interneuron-
specific GluA4 AMPARs. For the second aim, we will employ transgenic mouse models, biochemistry, neuron
culture, confocal light microscopy, and electrophysiology to test the hypothesis that direct binding of NPTX2 to
the NTD of GluA4 drives homeostatic scaling in disease-associated PVINs.
The applicant has proposed this work in part to further their long-term goal of establishing an independent
research career connecting the structure of synaptic proteins to their synaptic function. The candidate will
undertake extensive training in Cryo-EM and biophysics which will be facilitated by an expert mentoring team
composed of an AMPAR Cryo-EM expert, an AMPAR plasticity expert, and an expert in NPTX2, all of whom will
mentor the applicant through the transition to a tenure track academic position.
Terms: <Adhesion Molecule><Adhesions><Affinity><Binding><Binding Sites><Biochemical><Biochemistry><Biological Chemistry><Biology><Biophysics><Brain><Brain Nervous System><Cations><Cell Adhesion Molecule Gene><Cell Adhesion Molecules><Cell Body><Cell surface><Cells><Combining Site><Complex><Connector Neuron><Cryo-electron Microscopy><Cryoelectron Microscopy><Data><Disease><Disinhibition><Disorder><Dysfunction><Electron Cryomicroscopy><Electrophysiology><Electrophysiology (science)><Encephalon><Excitatory Synapse><Exhibits><Functional disorder><Future><Genetic><Genetics-Mutagenesis><Glutamate Receptor><Glutamates><Goals><Health><Human><Intercalary Neuron><Intercalated Neurons><Interneurons><Internuncial Cell><Internuncial Neuron><L-Glutamate><Learning><Membrane><Memory><Mental disorders><Mental health disorders><Mentors><Methods><Mice><Mice Mammals><Mission><Modeling><Modern Man><Molecular><Molecular Interaction><Murine><Mus><Mutagenesis><Mutagenesis Molecular Biology><N-terminal><NH2-terminal><NIH><National Institutes of Health><Nerve Cells><Nerve Unit><Nervous System Diseases><Nervous System Disorder><Neural Cell><Neurocyte><Neurohumor Receptors><Neurologic Disorders><Neurological Disorders><Neuromediator Receptors><Neurons><Neurophysiology / Electrophysiology><Neuroregulator Receptors><Neurosciences><Neurotransmitter Receptor><Parvalbumins><Pathology><Physiology><Physiopathology><Position><Positioning Attribute><Process><Property><Proteins><Psychiatric Disease><Psychiatric Disorder><Reactive Site><Receptor Protein><Regulation><Research><Role><Schizophrenia><Schizophrenic Disorders><Structural Models><Structure><Surface><Synapses><Synaptic><Synaptic plasticity><Techniques><Testing><Therapeutic><Training><Transgenic Mice><United States National Institutes of Health><Work><antagonism><antagonist><biophysical foundation><biophysical principles><biophysical sciences><career><cell adhesion protein><cryo-EM><cryoEM><cryogenic electron microscopy><dementia praecox><design><designing><electrophysiological><excitatory neuron><expectation><extracellular><functional outcomes><glutamatergic><human disease><improved><innovate><innovation><innovative><insight><light microscopy><membrane structure><mental illness><mouse model><murine model><mutant><neurological disease><neuronal><neuronal pentraxin><neuropsychiatric disease><neuropsychiatric disorder><particle><pathophysiology><pharmacologic><postsynaptic><presynaptic><prevent><preventing><psychiatric illness><psychological disorder><receptor><response><schizophrenic><social role><stoichiometry><structural biology><synapse><synapse function><synaptic function><tenure process><tenure track><therapeutic agent development><therapeutic development><therapeutic target>