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Open data
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Basic information
Entry | Database: PDB / ID: 8tkd | ||||||||||||
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Title | Human Type 3 IP3 Receptor - Preactivated State (+IP3/ATP) | ||||||||||||
![]() | Inositol 1,4,5-trisphosphate receptor type 3 | ||||||||||||
![]() | TRANSPORT PROTEIN / Ion Channel / Calcium Channel / Endoplasmic Reticulum | ||||||||||||
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 hexakisphosphate binding / inositol 1,4,5 trisphosphate binding / nuclear outer membrane / 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 / memory / platelet activation / response to calcium ion / Sensory perception of sweet, bitter, and umami (glutamate) taste / Glucagon-like Peptide-1 (GLP1) regulates insulin secretion / sensory perception of taste / apical part of cell / 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: 3.7 Å | ||||||||||||
![]() | Paknejad, N. / Sapuru, V. / Hite, R.K. | ||||||||||||
Funding support | ![]()
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![]() | ![]() Title: Structural titration reveals Ca-dependent conformational landscape of the IP receptor. Authors: Navid Paknejad / Vinay Sapuru / Richard K Hite / ![]() Abstract: Inositol 1,4,5-trisphosphate receptors (IPRs) are endoplasmic reticulum Ca channels whose biphasic dependence on cytosolic Ca gives rise to Ca oscillations that regulate fertilization, cell division ...Inositol 1,4,5-trisphosphate receptors (IPRs) are endoplasmic reticulum Ca channels whose biphasic dependence on cytosolic Ca gives rise to Ca oscillations that regulate fertilization, cell division and cell death. Despite the critical roles of IPR-mediated Ca responses, the structural underpinnings of the biphasic Ca dependence that underlies Ca oscillations are incompletely understood. Here, we collect cryo-EM images of an IPR with Ca concentrations spanning five orders of magnitude. Unbiased image analysis reveals that Ca binding does not explicitly induce conformational changes but rather biases a complex conformational landscape consisting of resting, preactivated, activated, and inhibited states. Using particle counts as a proxy for relative conformational free energy, we demonstrate that Ca binding at a high-affinity site allows IPRs to activate by escaping a low-energy resting state through an ensemble of preactivated states. At high Ca concentrations, IPRs preferentially enter an inhibited state stabilized by a second, low-affinity Ca binding site. Together, these studies provide a mechanistic basis for the biphasic Ca-dependence of IPR channel activity. | ||||||||||||
History |
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Structure visualization
Structure viewer | Molecule: ![]() ![]() |
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PDBx/mmCIF format | ![]() | 3.5 MB | Display | ![]() |
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-Validation report
Summary document | ![]() | 1.3 MB | Display | ![]() |
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Full document | ![]() | 1.4 MB | Display | |
Data in XML | ![]() | 211 KB | Display | |
Data in CIF | ![]() | 321.4 KB | Display | |
Arichive directory | ![]() ![]() | HTTPS FTP |
-Related structure data
Related structure data | ![]() 41347MC ![]() 8tk8C ![]() 8tkeC ![]() 8tkfC ![]() 8tkgC ![]() 8tkhC ![]() 8tkiC ![]() 8tl9C ![]() 8tlaC 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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Assembly
Deposited unit | ![]()
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Noncrystallographic symmetry (NCS) | NCS domain:
NCS domain segments: Ens-ID: ens_1
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