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- EMDB-36799: Human TWIK-related acid-sensitive potassium channel TASK3 at pH 6... -
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Open data
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Basic information
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Title | Human TWIK-related acid-sensitive potassium channel TASK3 at pH 6.0, 5 mM KCl and 135 mM NaCl | |||||||||||||||
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![]() | Acid-sensitive / potassium ion channel / C-type / gating mechanism / MEMBRANE PROTEIN | |||||||||||||||
Function / homology | ![]() TWIK-releated acid-sensitive K+ channel (TASK) / Phase 4 - resting membrane potential / stabilization of membrane potential / potassium ion leak channel activity / outward rectifier potassium channel activity / potassium ion import across plasma membrane / potassium channel activity / potassium ion transmembrane transport / potassium ion transport / synaptic vesicle / plasma membrane Similarity search - Function | |||||||||||||||
Biological species | ![]() | |||||||||||||||
Method | single particle reconstruction / cryo EM / Resolution: 3.68 Å | |||||||||||||||
![]() | Chen S / Lin H | |||||||||||||||
Funding support | ![]()
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![]() | ![]() Title: C-type inactivation and proton modulation mechanisms of the TASK3 channel. Authors: Huajian Lin / Junnan Li / Qiansen Zhang / Huaiyu Yang / Shanshuang Chen / ![]() Abstract: The TWIK-related acid-sensitive K channel 3 (TASK3) belongs to the two-pore domain (K2P) potassium channel family, which regulates cell excitability by mediating a constitutive "leak" potassium ...The TWIK-related acid-sensitive K channel 3 (TASK3) belongs to the two-pore domain (K2P) potassium channel family, which regulates cell excitability by mediating a constitutive "leak" potassium efflux in the nervous system. Extracellular acidification inhibits TASK3 channel, but the molecular mechanism by which channel inactivation is coupled to pH decrease remains unclear. Here, we report the cryo-electron microscopy structures of human TASK3 at neutral and acidic pH. Structural comparison revealed selectivity filter (SF) rearrangements upon acidification, characteristic of C-type inactivation, but with a unique structural basis. The extracellular mouth of the SF was prominently dilated and simultaneously blocked by a hydrophobic gate. His98 protonation shifted the conformational equilibrium between the conductive and C-type inactivated SF toward the latter by engaging a cation-π interaction with Trp78, consistent with molecular dynamics simulations and electrophysiological experiments. Our work illustrated how TASK3 is gated in response to extracellular pH change and implies how physiological stimuli might directly modulate the C-type gating of K2P channels. | |||||||||||||||
History |
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Structure visualization
Supplemental images |
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Downloads & links
-EMDB archive
Map data | ![]() | 28.7 MB | ![]() | |
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Header (meta data) | ![]() ![]() | 15.7 KB 15.7 KB | Display Display | ![]() |
Images | ![]() | 39.7 KB | ||
Filedesc metadata | ![]() | 5.6 KB | ||
Others | ![]() ![]() | 28.2 MB 28.2 MB | ||
Archive directory | ![]() ![]() | HTTPS FTP |
-Related structure data
Related structure data | ![]() 8k1qMC ![]() 8k1jC ![]() 8k1vC ![]() 8k1zC M: atomic model generated by this map C: citing same article ( |
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Similar structure data | Similarity search - Function & homology ![]() |
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Links
EMDB pages | ![]() ![]() |
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Related items in Molecule of the Month |
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Map
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Voxel size | X=Y=Z: 1.1 Å | ||||||||||||||||||||
Density |
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Symmetry | Space group: 1 | ||||||||||||||||||||
Details | EMDB XML:
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-Supplemental data
-Half map: #2
File | emd_36799_half_map_1.map | ||||||||||||
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Projections & Slices |
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Density Histograms |
-Half map: #1
File | emd_36799_half_map_2.map | ||||||||||||
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Density Histograms |
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Sample components
-Entire : CHS
Entire | Name: CHS |
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Components |
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-Supramolecule #1: CHS
Supramolecule | Name: CHS / type: complex / ID: 1 / Parent: 0 / Macromolecule list: #1 |
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Source (natural) | Organism: ![]() |
-Macromolecule #1: Potassium channel subfamily K member 9
Macromolecule | Name: Potassium channel subfamily K member 9 / type: protein_or_peptide / ID: 1 / Number of copies: 2 / Enantiomer: LEVO |
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Source (natural) | Organism: ![]() |
Molecular weight | Theoretical: 31.173238 KDa |
Recombinant expression | Organism: eukaryotic plasmids (others) |
Sequence | String: MKRQNVRTLS LIVCTFTYLL VGAAVFDALE SDHEMREEEK LKAEEIRIKG KYNISSEDYR QLELVILQSE PHRAGVQWKF AGSFYFAIT VITTIGYGHA APGTDAGKAF CMFYAVLGIP LTLVMFQSLG ERMNTFVRYL LKRIKKCCGM RNTDVSMENM V TVGFFSCM ...String: MKRQNVRTLS LIVCTFTYLL VGAAVFDALE SDHEMREEEK LKAEEIRIKG KYNISSEDYR QLELVILQSE PHRAGVQWKF AGSFYFAIT VITTIGYGHA APGTDAGKAF CMFYAVLGIP LTLVMFQSLG ERMNTFVRYL LKRIKKCCGM RNTDVSMENM V TVGFFSCM GTLCIGAAAF SQCEEWSFFH AYYYCFITLT TIGFGDYVAL QTKGALQKKP LYVAFSFMYI LVGLTVIGAF LN LVVLRFL TMNSEDERRD AENLYFQGVD AGLEVLFQ UniProtKB: Potassium channel subfamily K member 9 |
-Macromolecule #2: CHOLESTEROL HEMISUCCINATE
Macromolecule | Name: CHOLESTEROL HEMISUCCINATE / type: ligand / ID: 2 / Number of copies: 6 / Formula: Y01 |
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Molecular weight | Theoretical: 486.726 Da |
Chemical component information | ![]() ChemComp-Y01: |
-Macromolecule #3: POTASSIUM ION
Macromolecule | Name: POTASSIUM ION / type: ligand / ID: 3 / Number of copies: 2 / Formula: K |
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Molecular weight | Theoretical: 39.098 Da |
-Macromolecule #4: water
Macromolecule | Name: water / type: ligand / ID: 4 / Number of copies: 4 / Formula: HOH |
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Molecular weight | Theoretical: 18.015 Da |
Chemical component information | ![]() ChemComp-HOH: |
-Experimental details
-Structure determination
Method | cryo EM |
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![]() | single particle reconstruction |
Aggregation state | particle |
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Sample preparation
Buffer | pH: 8 Component:
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Vitrification | Cryogen name: NITROGEN / Chamber humidity: 100 % / Chamber temperature: 281.15 K / Instrument: FEI VITROBOT MARK IV |
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Electron microscopy
Microscope | FEI TITAN KRIOS |
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Image recording | Film or detector model: GATAN K3 (6k x 4k) / Average electron dose: 50.0 e/Å2 |
Electron beam | Acceleration voltage: 300 kV / Electron source: ![]() |
Electron optics | Illumination mode: FLOOD BEAM / Imaging mode: BRIGHT FIELD / Nominal defocus max: 2.5 µm / Nominal defocus min: 1.5 µm / Nominal magnification: 81000 |
Experimental equipment | ![]() Model: Titan Krios / Image courtesy: FEI Company |
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Image processing
Startup model | Type of model: OTHER |
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Final reconstruction | Applied symmetry - Point group: C2 (2 fold cyclic) / Resolution.type: BY AUTHOR / Resolution: 3.68 Å / Resolution method: FSC 0.143 CUT-OFF / Number images used: 291294 |
Initial angle assignment | Type: OTHER |
Final angle assignment | Type: OTHER |