Journal: Nature / Year: 2022 Title: Mechanisms of inhibition and activation of extrasynaptic αβ GABA receptors. Authors: Vikram Babu Kasaragod / Martin Mortensen / Steven W Hardwick / Ayla A Wahid / Valentina Dorovykh / Dimitri Y Chirgadze / Trevor G Smart / Paul S Miller / Abstract: Type A GABA (γ-aminobutyric acid) receptors represent a diverse population in the mammalian brain, forming pentamers from combinations of α-, β-, γ-, δ-, ε-, ρ-, θ- and π-subunits. αβ, ...Type A GABA (γ-aminobutyric acid) receptors represent a diverse population in the mammalian brain, forming pentamers from combinations of α-, β-, γ-, δ-, ε-, ρ-, θ- and π-subunits. αβ, α4βδ, α6βδ and α5βγ receptors favour extrasynaptic localization, and mediate an essential persistent (tonic) inhibitory conductance in many regions of the mammalian brain. Mutations of these receptors in humans are linked to epilepsy and insomnia. Altered extrasynaptic receptor function is implicated in insomnia, stroke and Angelman and Fragile X syndromes, and drugs targeting these receptors are used to treat postpartum depression. Tonic GABAergic responses are moderated to avoid excessive suppression of neuronal communication, and can exhibit high sensitivity to Zn blockade, in contrast to synapse-preferring α1βγ, α2βγ and α3βγ receptor responses. Here, to resolve these distinctive features, we determined structures of the predominantly extrasynaptic αβ GABA receptor class. An inhibited state bound by both the lethal paralysing agent α-cobratoxin and Zn was used in comparisons with GABA-Zn and GABA-bound structures. Zn nullifies the GABA response by non-competitively plugging the extracellular end of the pore to block chloride conductance. In the absence of Zn, the GABA signalling response initially follows the canonical route until it reaches the pore. In contrast to synaptic GABA receptors, expansion of the midway pore activation gate is limited and it remains closed, reflecting the intrinsic low efficacy that characterizes the extrasynaptic receptor. Overall, this study explains distinct traits adopted by αβ receptors that adapt them to a role in tonic signalling.
History
Deposition
Aug 2, 2021
-
Header (metadata) release
Feb 9, 2022
-
Map release
Feb 9, 2022
-
Update
Nov 15, 2023
-
Current status
Nov 15, 2023
Processing site: PDBe / Status: Released
-
Structure visualization
Movie
Surface view with section colored by density value
In the structure databanks used in Yorodumi, some data are registered as the other names, "COVID-19 virus" and "2019-nCoV". Here are the details of the virus and the list of structure data.
Jan 31, 2019. EMDB accession codes are about to change! (news from PDBe EMDB page)
EMDB accession codes are about to change! (news from PDBe EMDB page)
The allocation of 4 digits for EMDB accession codes will soon come to an end. Whilst these codes will remain in use, new EMDB accession codes will include an additional digit and will expand incrementally as the available range of codes is exhausted. The current 4-digit format prefixed with “EMD-” (i.e. EMD-XXXX) will advance to a 5-digit format (i.e. EMD-XXXXX), and so on. It is currently estimated that the 4-digit codes will be depleted around Spring 2019, at which point the 5-digit format will come into force.
The EM Navigator/Yorodumi systems omit the EMD- prefix.
Related info.:Q: What is EMD? / ID/Accession-code notation in Yorodumi/EM Navigator
Yorodumi is a browser for structure data from EMDB, PDB, SASBDB, etc.
This page is also the successor to EM Navigator detail page, and also detail information page/front-end page for Omokage search.
The word "yorodu" (or yorozu) is an old Japanese word meaning "ten thousand". "mi" (miru) is to see.
Related info.:EMDB / PDB / SASBDB / Comparison of 3 databanks / Yorodumi Search / Aug 31, 2016. New EM Navigator & Yorodumi / Yorodumi Papers / Jmol/JSmol / Function and homology information / Changes in new EM Navigator and Yorodumi