9b37
Open state of kainate receptor GluK2 in complex with agonist glutamate and positive allosteric modulator BPAM344 bound to one concanavalin A dimer. Composite map.
Structural highlights
FunctionGRIK2_RAT Ionotropic glutamate receptor. L-glutamate acts as an excitatory neurotransmitter at many synapses in the central nervous system. Binding of the excitatory neurotransmitter L-glutamate induces a conformation change, leading to the opening of the cation channel, and thereby converts the chemical signal to an electrical impulse. The receptor then desensitizes rapidly and enters a transient inactive state, characterized by the presence of bound agonist. May be involved in the transmission of light information from the retina to the hypothalamus. Modulates cell surface expression of NETO2 (By similarity).[1] [2] Publication Abstract from PubMedKainate receptors, a subclass of ionotropic glutamate receptors, are tetrameric ligand-gated ion channels that mediate excitatory neurotransmission(1-4). Kainate receptors modulate neuronal circuits and synaptic plasticity during the development and function of the central nervous system and are implicated in various neurological and psychiatric diseases, including epilepsy, depression, schizophrenia, anxiety and autism(5-11). Although structures of kainate receptor domains and subunit assemblies are available(12-18), the mechanism of kainate receptor gating remains poorly understood. Here we present cryo-electron microscopy structures of the kainate receptor GluK2 in the presence of the agonist glutamate and the positive allosteric modulators lectin concanavalin A and BPAM344. Concanavalin A and BPAM344 inhibit kainate receptor desensitization and prolong activation by acting as a spacer between the amino-terminal and ligand-binding domains and a stabilizer of the ligand-binding domain dimer interface, respectively. Channel opening involves the kinking of all four pore-forming M3 helices. Our structures reveal the molecular basis of kainate receptor gating, which could guide the development of drugs for treatment of neurological disorders. Kainate receptor channel opening and gating mechanism.,Gangwar SP, Yelshanskaya MV, Nadezhdin KD, Yen LY, Newton TP, Aktolun M, Kurnikova MG, Sobolevsky AI Nature. 2024 May 22. doi: 10.1038/s41586-024-07475-0. PMID:38778115[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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