| Structural highlights
Function
GRIA1_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. 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]
Publication Abstract from PubMed
AMPA-type glutamate receptors (AMPARs) mediate rapid signal transmission at excitatory synapses in the brain. Glutamate binding to the receptor's ligand-binding domains (LBDs) leads to ion channel activation and desensitization. Gating kinetics shape synaptic transmission and are strongly modulated by transmembrane AMPAR regulatory proteins (TARPs) through currently incompletely resolved mechanisms. Here, electron cryo-microscopy structures of the GluA1/2 TARP-gamma8 complex, in both open and desensitized states (at 3.5 A), reveal state-selective engagement of the LBDs by the large TARP-gamma8 loop ('beta1'), elucidating how this TARP stabilizes specific gating states. We further show how TARPs alter channel rectification, by interacting with the pore helix of the selectivity filter. Lastly, we reveal that the Q/R-editing site couples the channel constriction at the filter entrance to the gate, and forms the major cation binding site in the conduction path. Our results provide a mechanistic framework of how TARPs modulate AMPAR gating and conductance.
Mechanisms underlying TARP modulation of the GluA1/2-gamma8 AMPA receptor.,Herguedas B, Kohegyi BK, Dohrke JN, Watson JF, Zhang D, Ho H, Shaikh SA, Lape R, Krieger JM, Greger IH Nat Commun. 2022 Feb 8;13(1):734. doi: 10.1038/s41467-022-28404-7. PMID:35136046[3]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Bedoukian MA, Weeks AM, Partin KM. Different domains of the AMPA receptor direct stargazin-mediated trafficking and stargazin-mediated modulation of kinetics. J Biol Chem. 2006 Aug 18;281(33):23908-21. Epub 2006 Jun 22. PMID:16793768 doi:http://dx.doi.org/M600679200
- ↑ Schwenk J, Harmel N, Zolles G, Bildl W, Kulik A, Heimrich B, Chisaka O, Jonas P, Schulte U, Fakler B, Klocker N. Functional proteomics identify cornichon proteins as auxiliary subunits of AMPA receptors. Science. 2009 Mar 6;323(5919):1313-9. doi: 10.1126/science.1167852. PMID:19265014 doi:10.1126/science.1167852
- ↑ Herguedas B, Kohegyi BK, Dohrke JN, Watson JF, Zhang D, Ho H, Shaikh SA, Lape R, Krieger JM, Greger IH. Mechanisms underlying TARP modulation of the GluA1/2-γ8 AMPA receptor. Nat Commun. 2022 Feb 8;13(1):734. PMID:35136046 doi:10.1038/s41467-022-28404-7
|
