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Open data
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Basic information
Entry | Database: PDB / ID: 7t3q | ||||||||||||
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Title | IP3 and ATP bound type 3 IP3 receptor in the pre-active B state | ||||||||||||
![]() | Inositol 1,4,5-trisphosphate receptor type 3 | ||||||||||||
![]() | METAL TRANSPORT / IP3 receptor / calcium signaling | ||||||||||||
Function / homology | ![]() DAG and IP3 signaling / sensory perception of bitter taste / inositol 1,3,4,5 tetrakisphosphate binding / sensory perception of umami taste / inositol 1,4,5-trisphosphate-gated calcium channel activity / sensory perception of sweet taste / platelet dense tubular network membrane / Effects of PIP2 hydrolysis / Elevation of cytosolic Ca2+ levels / PLC beta mediated events ...DAG and IP3 signaling / sensory perception of bitter taste / inositol 1,3,4,5 tetrakisphosphate binding / sensory perception of umami taste / inositol 1,4,5-trisphosphate-gated calcium channel activity / sensory perception of sweet taste / platelet dense tubular network membrane / Effects of PIP2 hydrolysis / Elevation of cytosolic Ca2+ levels / PLC beta mediated events / inositol 1,4,5 trisphosphate binding / nuclear outer membrane / inositol hexakisphosphate binding / CLEC7A (Dectin-1) induces NFAT activation / transport vesicle membrane / cytoplasmic side of endoplasmic reticulum membrane / brush border / intracellularly gated calcium channel activity / Role of phospholipids in phagocytosis / calcium ion homeostasis / Ion homeostasis / release of sequestered calcium ion into cytosol / FCERI mediated Ca+2 mobilization / phosphatidylinositol binding / FCGR3A-mediated IL10 synthesis / Antigen activates B Cell Receptor (BCR) leading to generation of second messengers / secretory granule membrane / VEGFR2 mediated cell proliferation / sarcoplasmic reticulum / Regulation of insulin secretion / long-term synaptic potentiation / platelet activation / memory / response to calcium ion / Sensory perception of sweet, bitter, and umami (glutamate) taste / Glucagon-like Peptide-1 (GLP1) regulates insulin secretion / apical part of cell / sensory perception of taste / Ca2+ pathway / positive regulation of cytosolic calcium ion concentration / protein homotetramerization / receptor complex / G protein-coupled receptor signaling pathway / neuronal cell body / calcium ion binding / endoplasmic reticulum membrane / nucleolus / endoplasmic reticulum / nucleoplasm / membrane / plasma membrane / cytoplasm Similarity search - Function | ||||||||||||
Biological species | ![]() | ||||||||||||
Method | ELECTRON MICROSCOPY / single particle reconstruction / cryo EM / Resolution: 3.3 Å | ||||||||||||
![]() | Schmitz, E.A. / Takahashi, H. / Karakas, E. | ||||||||||||
Funding support | ![]()
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![]() | ![]() Title: Structural basis for activation and gating of IP receptors. Authors: Emily A Schmitz / Hirohide Takahashi / Erkan Karakas / ![]() Abstract: A pivotal component of the calcium (Ca) signaling toolbox in cells is the inositol 1,4,5-triphosphate (IP) receptor (IPR), which mediates Ca release from the endoplasmic reticulum (ER), controlling ...A pivotal component of the calcium (Ca) signaling toolbox in cells is the inositol 1,4,5-triphosphate (IP) receptor (IPR), which mediates Ca release from the endoplasmic reticulum (ER), controlling cytoplasmic and organellar Ca concentrations. IPRs are co-activated by IP and Ca, inhibited by Ca at high concentrations, and potentiated by ATP. However, the underlying molecular mechanisms are unclear. Here we report cryo-electron microscopy (cryo-EM) structures of human type-3 IPR obtained from a single dataset in multiple gating conformations: IP-ATP bound pre-active states with closed channels, IP-ATP-Ca bound active state with an open channel, and IP-ATP-Ca bound inactive state with a closed channel. The structures demonstrate how IP-induced conformational changes prime the receptor for activation by Ca, how Ca binding leads to channel opening, and how ATP modulates the activity, providing insights into the long-sought questions regarding the molecular mechanism underpinning receptor activation and gating. | ||||||||||||
History |
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Structure visualization
Structure viewer | Molecule: ![]() ![]() |
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Downloads & links
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Download
PDBx/mmCIF format | ![]() | 1.5 MB | Display | ![]() |
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PDB format | ![]() | Display | ![]() | |
PDBx/mmJSON format | ![]() | Tree view | ![]() | |
Others | ![]() |
-Validation report
Summary document | ![]() | 1.9 MB | Display | ![]() |
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Full document | ![]() | 2 MB | Display | |
Data in XML | ![]() | 215 KB | Display | |
Data in CIF | ![]() | 328.1 KB | Display | |
Arichive directory | ![]() ![]() | HTTPS FTP |
-Related structure data
Related structure data | ![]() 25668MC ![]() 7t3pC ![]() 7t3rC ![]() 7t3tC ![]() 7t3uC M: map data used to model this data C: citing same article ( |
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Similar structure data | Similarity search - Function & homology ![]() |
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Links
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Assembly
Deposited unit | ![]()
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Components
#1: Protein | Mass: 299325.875 Da / Num. of mol.: 4 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() ![]() #2: Chemical | ChemComp-ZN / #3: Chemical | ChemComp-I3P / #4: Chemical | ChemComp-ATP / Has ligand of interest | N | Has protein modification | Y | |
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-Experimental details
-Experiment
Experiment | Method: ELECTRON MICROSCOPY |
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EM experiment | Aggregation state: PARTICLE / 3D reconstruction method: single particle reconstruction |
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Sample preparation
Component | Name: Inositol 1,4,5-trisphosphate receptor type 3 / Type: COMPLEX / Entity ID: #1 / Source: RECOMBINANT | ||||||||||||||||||||||||||||||||||||||||||||||||||
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Molecular weight | Value: 1.2 MDa / Experimental value: NO | ||||||||||||||||||||||||||||||||||||||||||||||||||
Source (natural) | Organism: ![]() | ||||||||||||||||||||||||||||||||||||||||||||||||||
Source (recombinant) | Organism: ![]() ![]() | ||||||||||||||||||||||||||||||||||||||||||||||||||
Buffer solution | pH: 8 Details: IP3, ATP, and CaCl2 were added before cryo-grid preparation. | ||||||||||||||||||||||||||||||||||||||||||||||||||
Buffer component |
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Specimen | Conc.: 1.8 mg/ml / Embedding applied: NO / Shadowing applied: NO / Staining applied: NO / Vitrification applied: YES | ||||||||||||||||||||||||||||||||||||||||||||||||||
Specimen support | Grid material: COPPER / Grid mesh size: 300 divisions/in. / Grid type: Quantifoil R1.2/1.3 | ||||||||||||||||||||||||||||||||||||||||||||||||||
Vitrification | Instrument: FEI VITROBOT MARK IV / Cryogen name: ETHANE / Humidity: 100 % / Chamber temperature: 281 K |
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Electron microscopy imaging
Experimental equipment | ![]() Model: Titan Krios / Image courtesy: FEI Company |
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Microscopy | Model: FEI TITAN KRIOS |
Electron gun | Electron source: ![]() |
Electron lens | Mode: BRIGHT FIELD / Nominal magnification: 105000 X / Nominal defocus max: 1600 nm / Nominal defocus min: 800 nm |
Image recording | Electron dose: 60 e/Å2 / Film or detector model: GATAN K3 BIOQUANTUM (6k x 4k) / Num. of grids imaged: 4 / Num. of real images: 42361 |
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Processing
EM software |
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CTF correction | Type: PHASE FLIPPING AND AMPLITUDE CORRECTION | ||||||||||||||||||||||||||||||
Particle selection | Num. of particles selected: 846122 | ||||||||||||||||||||||||||||||
Symmetry | Point symmetry: C4 (4 fold cyclic) | ||||||||||||||||||||||||||||||
3D reconstruction | Resolution: 3.3 Å / Resolution method: FSC 0.143 CUT-OFF / Num. of particles: 153765 / Num. of class averages: 1 / Symmetry type: POINT | ||||||||||||||||||||||||||||||
Atomic model building | Protocol: FLEXIBLE FIT / Space: REAL | ||||||||||||||||||||||||||||||
Atomic model building | PDB-ID: 6UQK Accession code: 6UQK / Source name: PDB / Type: experimental model |