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Open data
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Basic information
Entry | Database: EMDB / ID: EMD-7537 | |||||||||
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Title | Cryo-EM structure of the human SK4/calmodulin channel complex | |||||||||
![]() | human SK4/calmodulin channel complex: sharpened, filtered map | |||||||||
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![]() | ion channel / neuroscience / calmodulin / MEMBRANE PROTEIN | |||||||||
Function / homology | ![]() intermediate conductance calcium-activated potassium channel activity / small conductance calcium-activated potassium channel activity / saliva secretion / Ca2+ activated K+ channels / calcium-activated potassium channel activity / stabilization of membrane potential / positive regulation of potassium ion transmembrane transport / cell volume homeostasis / CaM pathway / Cam-PDE 1 activation ...intermediate conductance calcium-activated potassium channel activity / small conductance calcium-activated potassium channel activity / saliva secretion / Ca2+ activated K+ channels / calcium-activated potassium channel activity / stabilization of membrane potential / positive regulation of potassium ion transmembrane transport / cell volume homeostasis / CaM pathway / Cam-PDE 1 activation / Sodium/Calcium exchangers / phospholipid translocation / Calmodulin induced events / Reduction of cytosolic Ca++ levels / CREB1 phosphorylation through the activation of CaMKII/CaMKK/CaMKIV cascasde / Activation of Ca-permeable Kainate Receptor / Loss of phosphorylation of MECP2 at T308 / CREB1 phosphorylation through the activation of Adenylate Cyclase / PKA activation / negative regulation of high voltage-gated calcium channel activity / CaMK IV-mediated phosphorylation of CREB / Glycogen breakdown (glycogenolysis) / positive regulation of cyclic-nucleotide phosphodiesterase activity / organelle localization by membrane tethering / negative regulation of calcium ion export across plasma membrane / CLEC7A (Dectin-1) induces NFAT activation / mitochondrion-endoplasmic reticulum membrane tethering / autophagosome membrane docking / regulation of cardiac muscle cell action potential / Activation of RAC1 downstream of NMDARs / immune system process / positive regulation of ryanodine-sensitive calcium-release channel activity / positive regulation of T cell receptor signaling pathway / regulation of cell communication by electrical coupling involved in cardiac conduction / Negative regulation of NMDA receptor-mediated neuronal transmission / negative regulation of peptidyl-threonine phosphorylation / Synthesis of IP3 and IP4 in the cytosol / Unblocking of NMDA receptors, glutamate binding and activation / Phase 0 - rapid depolarisation / negative regulation of ryanodine-sensitive calcium-release channel activity / protein phosphatase activator activity / RHO GTPases activate PAKs / : / Ion transport by P-type ATPases / Long-term potentiation / Uptake and function of anthrax toxins / Regulation of MECP2 expression and activity / Calcineurin activates NFAT / potassium channel activity / catalytic complex / DARPP-32 events / detection of calcium ion / regulation of cardiac muscle contraction / regulation of ryanodine-sensitive calcium-release channel activity / Smooth Muscle Contraction / cellular response to interferon-beta / RHO GTPases activate IQGAPs / regulation of cardiac muscle contraction by regulation of the release of sequestered calcium ion / calcium channel inhibitor activity / eNOS activation / Protein methylation / regulation of release of sequestered calcium ion into cytosol by sarcoplasmic reticulum / Activation of AMPK downstream of NMDARs / Tetrahydrobiopterin (BH4) synthesis, recycling, salvage and regulation / Ion homeostasis / : / titin binding / regulation of calcium-mediated signaling / positive regulation of protein autophosphorylation / voltage-gated potassium channel complex / sperm midpiece / potassium ion transmembrane transport / calcium channel complex / substantia nigra development / adenylate cyclase activator activity / Ras activation upon Ca2+ influx through NMDA receptor / regulation of heart rate / sarcomere / FCERI mediated Ca+2 mobilization / protein serine/threonine kinase activator activity / FCGR3A-mediated IL10 synthesis / potassium ion transport / VEGFR2 mediated vascular permeability / Antigen activates B Cell Receptor (BCR) leading to generation of second messengers / VEGFR2 mediated cell proliferation / regulation of cytokinesis / positive regulation of peptidyl-threonine phosphorylation / establishment of localization in cell / Translocation of SLC2A4 (GLUT4) to the plasma membrane / spindle microtubule / positive regulation of protein secretion / RAF activation / positive regulation of receptor signaling pathway via JAK-STAT / response to calcium ion / positive regulation of protein serine/threonine kinase activity / Transcriptional activation of mitochondrial biogenesis / Stimuli-sensing channels / cellular response to type II interferon / G2/M transition of mitotic cell cycle / defense response Similarity search - Function | |||||||||
Biological species | ![]() | |||||||||
Method | single particle reconstruction / cryo EM / Resolution: 3.4 Å | |||||||||
![]() | Lee CH / MacKinnon R | |||||||||
Funding support | ![]()
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![]() | ![]() Title: Activation mechanism of a human SK-calmodulin channel complex elucidated by cryo-EM structures. Authors: Chia-Hsueh Lee / Roderick MacKinnon / ![]() Abstract: Small-conductance Ca-activated K (SK) channels mediate neuron excitability and are associated with synaptic transmission and plasticity. They also regulate immune responses and the size of blood ...Small-conductance Ca-activated K (SK) channels mediate neuron excitability and are associated with synaptic transmission and plasticity. They also regulate immune responses and the size of blood cells. Activation of SK channels requires calmodulin (CaM), but how CaM binds and opens SK channels has been unclear. Here we report cryo-electron microscopy (cryo-EM) structures of a human SK4-CaM channel complex in closed and activated states at 3.4- and 3.5-angstrom resolution, respectively. Four CaM molecules bind to one channel tetramer. Each lobe of CaM serves a distinct function: The C-lobe binds to the channel constitutively, whereas the N-lobe interacts with the S4-S5 linker in a Ca-dependent manner. The S4-S5 linker, which contains two distinct helices, undergoes conformational changes upon CaM binding to open the channel pore. These structures reveal the gating mechanism of SK channels and provide a basis for understanding SK channel pharmacology. | |||||||||
History |
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Structure visualization
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Structure viewer | EM map: ![]() ![]() ![]() |
Supplemental images |
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Downloads & links
-EMDB archive
Map data | ![]() | 96.3 MB | ![]() | |
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Header (meta data) | ![]() ![]() | 14.6 KB 14.6 KB | Display Display | ![]() |
Images | ![]() | 189.2 KB | ||
Filedesc metadata | ![]() | 5.5 KB | ||
Others | ![]() | 76.3 MB | ||
Archive directory | ![]() ![]() | HTTPS FTP |
-Related structure data
Related structure data | ![]() 6cnmMC ![]() 7538C ![]() 7539C ![]() 6cnnC ![]() 6cnoC C: citing same article ( M: atomic model generated by this map |
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Similar structure data |
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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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Annotation | human SK4/calmodulin channel complex: sharpened, filtered map | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Voxel size | X=Y=Z: 1.03 Å | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Density |
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Symmetry | Space group: 1 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Details | EMDB XML:
CCP4 map header:
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-Supplemental data
-Additional map: human SK4/calmodulin channel complex: unsharpened, unfiltered map
File | emd_7537_additional.map | ||||||||||||
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Annotation | human SK4/calmodulin channel complex: unsharpened, unfiltered map | ||||||||||||
Projections & Slices |
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Density Histograms |
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Sample components
-Entire : human SK4/calmodulin channel complex
Entire | Name: human SK4/calmodulin channel complex |
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Components |
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-Supramolecule #1: human SK4/calmodulin channel complex
Supramolecule | Name: human SK4/calmodulin channel complex / type: complex / ID: 1 / Parent: 0 / Macromolecule list: #1-#2 |
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Source (natural) | Organism: ![]() |
-Macromolecule #1: Intermediate conductance calcium-activated potassium channel protein 4
Macromolecule | Name: Intermediate conductance calcium-activated potassium channel protein 4 type: protein_or_peptide / ID: 1 / Number of copies: 4 / Enantiomer: LEVO |
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Source (natural) | Organism: ![]() |
Molecular weight | Theoretical: 47.758496 KDa |
Recombinant expression | Organism: ![]() |
Sequence | String: MGGDLVLGLG ALRRRKRLLE QEKSLAGWAL VLAGTGIGLM VLHAEMLWFG GCSWALYLFL VKCTISISTF LLLCLIVAFH AKEVQLFMT DNGLRDWRVA LTGRQAAQIV LELVVCGLHP APVRGPPCVQ DLGAPLTSPQ PWPGFLGQGE ALLSLAMLLR L YLVPRAVL ...String: MGGDLVLGLG ALRRRKRLLE QEKSLAGWAL VLAGTGIGLM VLHAEMLWFG GCSWALYLFL VKCTISISTF LLLCLIVAFH AKEVQLFMT DNGLRDWRVA LTGRQAAQIV LELVVCGLHP APVRGPPCVQ DLGAPLTSPQ PWPGFLGQGE ALLSLAMLLR L YLVPRAVL LRSGVLLNAS YRSIGALNQV RFRHWFVAKL YMNTHPGRLL LGLTLGLWLT TAWVLSVAER QAVNATGHLS DT LWLIPIT FLTIGYGDVV PGTMWGKIVC LCTGVMGVCC TALLVAVVAR KLEFNKAEKH VHNFMMDIQY TKEMKESAAR VLQ EAWMFY KHTRRKESHA ARRHQRKLLA AINAFRQVRL KHRKLREQVN SMVDISKMHM ILYDLQQNLS SSHRALEKQI DTLA GKLDA LTELLSTALG PRQLPEPSQQ SK UniProtKB: Intermediate conductance calcium-activated potassium channel protein 4 |
-Macromolecule #2: Calmodulin-1
Macromolecule | Name: Calmodulin-1 / type: protein_or_peptide / ID: 2 / Number of copies: 4 / Enantiomer: LEVO |
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Source (natural) | Organism: ![]() |
Molecular weight | Theoretical: 16.852545 KDa |
Recombinant expression | Organism: ![]() |
Sequence | String: MADQLTEEQI AEFKEAFSLF DKDGDGTITT KELGTVMRSL GQNPTEAELQ DMINEVDADG NGTIDFPEFL TMMARKMKDT DSEEEIREA FRVFDKDGNG YISAAELRHV MTNLGEKLTD EEVDEMIREA DIDGDGQVNY EEFVQMMTAK UniProtKB: Calmodulin-1 |
-Macromolecule #3: POTASSIUM ION
Macromolecule | Name: POTASSIUM ION / type: ligand / ID: 3 / Number of copies: 5 / Formula: K |
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Molecular weight | Theoretical: 39.098 Da |
-Macromolecule #4: (2S)-3-(hexadecanoyloxy)-2-[(9Z)-octadec-9-enoyloxy]propyl 2-(tri...
Macromolecule | Name: (2S)-3-(hexadecanoyloxy)-2-[(9Z)-octadec-9-enoyloxy]propyl 2-(trimethylammonio)ethyl phosphate type: ligand / ID: 4 / Number of copies: 4 / Formula: POV |
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Molecular weight | Theoretical: 760.076 Da |
Chemical component information | ![]() ChemComp-POV: |
-Macromolecule #5: DODECYL-BETA-D-MALTOSIDE
Macromolecule | Name: DODECYL-BETA-D-MALTOSIDE / type: ligand / ID: 5 / Number of copies: 8 / Formula: LMT |
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Molecular weight | Theoretical: 510.615 Da |
Chemical component information | ![]() ChemComp-LMT: |
-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 |
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Vitrification | Cryogen name: ETHANE |
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Electron microscopy
Microscope | FEI TITAN KRIOS |
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Image recording | Film or detector model: GATAN K2 SUMMIT (4k x 4k) / Average electron dose: 75.0 e/Å2 |
Electron beam | Acceleration voltage: 300 kV / Electron source: ![]() |
Electron optics | Illumination mode: FLOOD BEAM / Imaging mode: BRIGHT FIELD |
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: C4 (4 fold cyclic) / Resolution.type: BY AUTHOR / Resolution: 3.4 Å / Resolution method: FSC 0.143 CUT-OFF / Number images used: 42422 |
Initial angle assignment | Type: PROJECTION MATCHING |
Final angle assignment | Type: PROJECTION MATCHING |