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Published on: August 16, 2018
JNJ-55511118 Stabilizes a Desensitized-like Conformation of γ8-Containing AMPA Receptors through Long-Range
Paola Carrillo Flores1, Vladimir Berka1, Vasanthi Jayaraman1
1Department of Biochemistry and Molecular Biology, University of Texas Health Science Center, Houston, TX, USA.
JNJ-118, a selective inhibitor, stabilizes desensitized AMPA receptors (AMPARs) by modulating their structure. This drug acts as a long-range allosteric modulator, inhibiting receptor function without dissociating auxiliary proteins.
Area of Science:
- Neuroscience
- Molecular Biology
- Pharmacology
Background:
- AMPA receptors (AMPARs) are glutamate-gated ion channels crucial for synaptic plasticity.
- TARP γ8 is an auxiliary protein that modulates AMPAR function.
- JNJ-55511118 (JNJ-118) selectively inhibits γ8-containing AMPARs.
Purpose of the Study:
- To elucidate the mechanism by which JNJ-118 inhibits agonist-bound AMPARs.
- To investigate the structural and conformational changes induced by JNJ-118 in AMPAR-γ8 complexes.
Main Methods:
- Single-molecule fluorescence resonance energy transfer (smFRET)
- Fluorescence lifetime imaging (FLIM)
- Electrophysiology
Main Results:
- JNJ-118 shifts glutamate-bound AMPAR-γ8 toward a desensitized-like conformation.
- The drug destabilizes the ligand-binding domain dimer interface.
- Functional assays show allosteric competition between JNJ-118 and cyclothiazide.
- γ8 remains associated with the receptor even when the dimer interface is altered.
Conclusions:
- JNJ-118 acts as a long-range allosteric modulator of agonist-bound AMPAR-γ8.
- It stabilizes a desensitized-like inhibited state without disrupting the AMPAR-γ8 complex.
- This provides insight into the mechanism of selective AMPAR inhibition.
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