Positive and negative allosteric modulation of GluK2 kainate receptors by BPAM344 and antiepileptic perampanel

Highlights

• •We present cryo-EM structures of kainate receptor GluK2 with different ligands
• •Two molecules of positive allosteric modulator BPAM344 bind per LBD dimer interface
• •BPAM344 stabilizes the competitive inhibitor DNQX-bound closed state of GluK2
• •Antiepileptic perampanel binds at two sites in the ion channel extracellular collar

Summary

Kainate receptors (KARs) are a subtype of ionotropic glutamate receptors that control synaptic transmission in the central nervous system and are implicated in neurological, psychiatric, and neurodevelopmental disorders. Understanding the regulation of KAR function by small molecules is essential for exploring these receptors as drug targets. Here, we present cryoelectron microscopy (cryo-EM) structures of KAR GluK2 in complex with the positive allosteric modulator BPAM344, competitive antagonist DNQX, and negative allosteric modulator, antiepileptic drug perampanel. Our structures show that two BPAM344 molecules bind per ligand-binding domain dimer interface. In the absence of an agonist or in the presence of DNQX, BPAM344 stabilizes GluK2 in the closed state. The closed state is also stabilized by perampanel, which binds to the ion channel extracellular collar sites located in two out of four GluK2 subunits. The molecular mechanisms of positive and negative allosteric modulation of KAR provide a guide for developing new therapeutic strategies.

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