| Structural highlights
Function
[GRIA2_RAT] Receptor for glutamate that functions as ligand-gated ion channel in the central nervous system and plays an important role in excitatory synaptic transmission. 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. In the presence of CACNG4 or CACNG7 or CACNG8, shows resensitization which is characterized by a delayed accumulation of current flux upon continued application of glutamate.[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14]
Publication Abstract from PubMed
Fast excitatory neurotransmission is mediated by AMPA-subtype ionotropic glutamate receptors (AMPARs). AMPARs, localized at post-synaptic densities, are regulated by transmembrane auxiliary subunits that modulate AMPAR assembly, trafficking, gating, and pharmacology. Aberrancies in AMPAR-mediated signaling are associated with numerous neurological disorders. Here, we report cryo-EM structures of an AMPAR in complex with the auxiliary subunit GSG1L in the closed and desensitized states. GSG1L favors the AMPAR desensitized state, where channel closure is facilitated by profound structural rearrangements in the AMPAR extracellular domain, with ligand-binding domain dimers losing their local 2-fold rotational symmetry. Our structural and functional experiments suggest that AMPAR auxiliary subunits share a modular architecture and use a common transmembrane scaffold for distinct extracellular modules to differentially regulate AMPAR gating. By comparing the AMPAR-GSG1L complex structures, we map conformational changes accompanying AMPAR recovery from desensitization and reveal structural bases for regulation of synaptic transmission by auxiliary subunits.
Structural Bases of Desensitization in AMPA Receptor-Auxiliary Subunit Complexes.,Twomey EC, Yelshanskaya MV, Grassucci RA, Frank J, Sobolevsky AI Neuron. 2017 May 3;94(3):569-580.e5. doi: 10.1016/j.neuron.2017.04.025. PMID:28472657[15]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
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- ↑ Twomey EC, Yelshanskaya MV, Grassucci RA, Frank J, Sobolevsky AI. Structural Bases of Desensitization in AMPA Receptor-Auxiliary Subunit Complexes. Neuron. 2017 May 3;94(3):569-580.e5. doi: 10.1016/j.neuron.2017.04.025. PMID:28472657 doi:https://dx.doi.org/10.1016/j.neuron.2017.04.025
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