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- EMDB-47768: Cryo-EM structure of human TWIK-2 at pH 7.5 -

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Basic information

Entry
Database: EMDB / ID: EMD-47768
TitleCryo-EM structure of human TWIK-2 at pH 7.5
Map data
Sample
  • Complex: Two-pore domain Weak Inwardly rectifying K+ channel 2 (TWIK2)
    • Protein or peptide: Potassium channel subfamily K member 6
  • Ligand: DECANE
  • Ligand: POTASSIUM ION
KeywordsPotassium ion channel K2P / TRANSPORT PROTEIN
Function / homology
Function and homology information


regulation of lysosome size / Tandem of pore domain in a weak inwardly rectifying K+ channels (TWIK) / Phase 4 - resting membrane potential / potassium ion leak channel activity / regulation of resting membrane potential / inward rectifier potassium channel activity / negative regulation of systemic arterial blood pressure / outward rectifier potassium channel activity / positive regulation of NLRP3 inflammasome complex assembly / potassium channel activity ...regulation of lysosome size / Tandem of pore domain in a weak inwardly rectifying K+ channels (TWIK) / Phase 4 - resting membrane potential / potassium ion leak channel activity / regulation of resting membrane potential / inward rectifier potassium channel activity / negative regulation of systemic arterial blood pressure / outward rectifier potassium channel activity / positive regulation of NLRP3 inflammasome complex assembly / potassium channel activity / voltage-gated potassium channel complex / potassium ion transmembrane transport / potassium ion transport / late endosome membrane / lysosomal membrane / metal ion binding / plasma membrane
Similarity search - Function
Two pore domain potassium channel, TWIK-2 / Two pore domain potassium channel, TWIK family / Two pore domain potassium channel, TASK family / Two pore domain potassium channel / Potassium channel domain / Ion channel
Similarity search - Domain/homology
Potassium channel subfamily K member 6
Similarity search - Component
Biological speciesHomo sapiens (human)
Methodsingle particle reconstruction / cryo EM / Resolution: 3.67 Å
AuthorsMa Q / Kumar A / Navratna V / Mosalaganti S
Funding support1 items
OrganizationGrant numberCountry
Other government
CitationJournal: Nat Commun / Year: 2026
Title: Insights into the structure and modulation of human TWIK-2.
Authors: Qianqian Ma / Ciria C Hernandez / Vikas Navratna / Arvind Kumar / Jaimin K Rana / Jiameng Zong / Abraham Lee / Shyamal Mosalaganti /
Abstract: The Tandem of pore domain in a Weak Inward Rectifying K channel 2 (TWIK-2; KCNK6) is a member of the Two-Pore Domain K (K) channel family, which is associated with pulmonary hypertension, lung ...The Tandem of pore domain in a Weak Inward Rectifying K channel 2 (TWIK-2; KCNK6) is a member of the Two-Pore Domain K (K) channel family, which is associated with pulmonary hypertension, lung injury, and inflammation. Despite its physiological relevance, the structure, regulatory mechanisms, and selective modulators of TWIK-2 remain largely unknown. Here, we present a 3.7 Å single particle cryo-electron microscopy structure of human TWIK-2 and highlight its conserved and distinctive features. Using automated whole-cell patch clamp recordings, we demonstrate that gating in TWIK-2 is voltage-dependent and insensitive to changes in the extracellular pH. We identify key residues that influence TWIK-2 activity by employing site-directed mutagenesis and provide insights into the possible lipid-mediated mechanism of TWIK-2 regulation. Additionally, we demonstrate the application of high-throughput automated whole-cell patch clamp platforms to screen small molecule modulators of TWIK-2. Our work serves as a foundation for designing high-throughput small molecule screening campaigns to identify specific high-affinity TWIK-2 modulators, including promising- anti-inflammatory therapeutics.
History
DepositionNov 7, 2024-
Header (metadata) releaseFeb 11, 2026-
Map releaseFeb 11, 2026-
UpdateFeb 11, 2026-
Current statusFeb 11, 2026Processing site: RCSB / Status: Released

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Structure visualization

Supplemental images

emd_47768.png

Downloads & links

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Map

FileDownload / File: emd_47768.map.gz / Format: CCP4 / Size: 64 MB / Type: IMAGE STORED AS FLOATING POINT NUMBER (4 BYTES)
Projections & slices

Image control

Size
Brightness
Contrast
Others
AxesZ (Sec.)Y (Row.)X (Col.)
0.83 Å/pix.
x 256 pix.
= 212.48 Å		0.83 Å/pix.
x 256 pix.
= 212.48 Å		0.83 Å/pix.
x 256 pix.
= 212.48 Å

Surface

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Images are generated by Spider.

Voxel sizeX=Y=Z: 0.83 Å
Density

Histogram

Histogram (log scale)
Contour LevelBy AUTHOR: 0.18
Minimum - Maximum-1.5415087 - 2.1757178
Average (Standard dev.)0.0026746453 (±0.032125965)
SymmetrySpace group: 1
Details

EMDB XML:

Map geometry
Axis orderXYZ
Origin000
Dimensions256256256
Spacing256256256
CellA=B=C: 212.48 Å
α=β=γ: 90.0 °

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Supplemental data

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Mask #1

Fileemd_47768_msk_1.map
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Half map: #2

Fileemd_47768_half_map_1.map
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Half map: #1

Fileemd_47768_half_map_2.map
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Sample components

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Entire : Two-pore domain Weak Inwardly rectifying K+ channel 2 (TWIK2)

EntireName: Two-pore domain Weak Inwardly rectifying K+ channel 2 (TWIK2)
Components
  • Complex: Two-pore domain Weak Inwardly rectifying K+ channel 2 (TWIK2)
    • Protein or peptide: Potassium channel subfamily K member 6
  • Ligand: DECANE
  • Ligand: POTASSIUM ION

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Supramolecule #1: Two-pore domain Weak Inwardly rectifying K+ channel 2 (TWIK2)

SupramoleculeName: Two-pore domain Weak Inwardly rectifying K+ channel 2 (TWIK2)
type: complex / ID: 1 / Parent: 0 / Macromolecule list: #1
Details: Full length human TWIK2 expressed as recombinant protein in mamalian cells.
Source (natural)Organism: Homo sapiens (human)
Molecular weightTheoretical: 63 KDa

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Macromolecule #1: Potassium channel subfamily K member 6

MacromoleculeName: Potassium channel subfamily K member 6 / type: protein_or_peptide / ID: 1 / Number of copies: 2 / Enantiomer: LEVO
Source (natural)Organism: Homo sapiens (human)
Molecular weightTheoretical: 33.775113 KDa
Recombinant expressionOrganism: Homo sapiens (human)
SequenceString: MRRGALLAGA LAAYAAYLVL GALLVARLEG PHEARLRAEL ETLRAQLLQR SPCVAAPALD AFVERVLAAG RLGRVVLANA SGSANASDP AWDFASALFF ASTLITTVGY GYTTPLTDAG KAFSIAFALL GVPTTMLLLT ASAQRLSLLL THVPLSWLSM R WGWDPRRA ...String:
MRRGALLAGA LAAYAAYLVL GALLVARLEG PHEARLRAEL ETLRAQLLQR SPCVAAPALD AFVERVLAAG RLGRVVLANA SGSANASDP AWDFASALFF ASTLITTVGY GYTTPLTDAG KAFSIAFALL GVPTTMLLLT ASAQRLSLLL THVPLSWLSM R WGWDPRRA ACWHLVALLG VVVTVCFLVP AVIFAHLEEA WSFLDAFYFC FISLSTIGLG DYVPGEAPGQ PYRALYKVLV TV YLFLGLV AMVLVLQTFR HVSDLHGLTE LILLPPPCPA SFNADEDDRV DILGPQPESH QQLSASSHTD YASIPR

UniProtKB: Potassium channel subfamily K member 6

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Macromolecule #2: DECANE

MacromoleculeName: DECANE / type: ligand / ID: 2 / Number of copies: 7 / Formula: D10
Molecular weightTheoretical: 142.282 Da
Chemical component information

ChemComp-D10:
DECANE

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Macromolecule #3: POTASSIUM ION

MacromoleculeName: POTASSIUM ION / type: ligand / ID: 3 / Number of copies: 3 / Formula: K
Molecular weightTheoretical: 39.098 Da

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Experimental details

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Structure determination

Methodcryo EM
Processingsingle particle reconstruction
Aggregation stateparticle

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Sample preparation

Concentration2.3 mg/mL
BufferpH: 7.5
Component:
ConcentrationFormulaName
25.0 mMTris4-(2-hydroxyethyl)piperazine-1-ethanesulfonic acid
150.0 mMKClPotassium Chloride
0.1 %DMNGDecyl maltose neopentyl glycol

Details: 25 mM Tris-HCl, 150 mM KCl, 0.1% DMNG
GridModel: UltrAuFoil R1.2/1.3 / Material: GOLD / Mesh: 300 / Support film - Material: GOLD / Support film - topology: HOLEY / Pretreatment - Type: GLOW DISCHARGE / Pretreatment - Time: 60 sec. / Pretreatment - Atmosphere: AIR / Pretreatment - Pressure: 0.026000000000000002 kPa / Details: 15 mA current
VitrificationCryogen name: ETHANE / Chamber humidity: 100 % / Chamber temperature: 277 K / Instrument: FEI VITROBOT MARK IV
DetailsTWIK2 in DMNG micelle, purified by Strep-Tactin affinity chromotography.

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Electron microscopy

MicroscopeTFS KRIOS
Image recordingFilm or detector model: GATAN K3 BIOCONTINUUM (6k x 4k) / Digitization - Dimensions - Width: 5760 pixel / Digitization - Dimensions - Height: 4092 pixel / Number grids imaged: 2 / Average exposure time: 2.0 sec. / Average electron dose: 60.0 e/Å2
Electron beamAcceleration voltage: 300 kV / Electron source: FIELD EMISSION GUN
Electron opticsC2 aperture diameter: 100.0 µm / Illumination mode: FLOOD BEAM / Imaging mode: BRIGHT FIELD / Cs: 2.7 mm / Nominal defocus max: 2.5 µm / Nominal defocus min: 0.8 µm
Sample stageSpecimen holder model: FEI TITAN KRIOS AUTOGRID HOLDER / Cooling holder cryogen: NITROGEN
Experimental equipment
Model: Titan Krios / Image courtesy: FEI Company

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Image processing

CTF correctionType: PHASE FLIPPING AND AMPLITUDE CORRECTION
Startup modelType of model: NONE
Final reconstructionResolution.type: BY AUTHOR / Resolution: 3.67 Å / Resolution method: FSC 0.143 CUT-OFF / Software - Name: cryoSPARC (ver. 4.5) / Number images used: 104997
Initial angle assignmentType: MAXIMUM LIKELIHOOD / Software - Name: cryoSPARC (ver. 4.5)
Final angle assignmentType: MAXIMUM LIKELIHOOD
FSC plot (resolution estimation)

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Atomic model buiding 1

RefinementProtocol: RIGID BODY FIT
Output model

PDB-9e94:
Cryo-EM structure of human TWIK-2 at pH 7.5

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