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Open data
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Basic information
Entry | Database: PDB / ID: 8sgi | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Title | Cryo-EM structure of human NCX1 in complex with SEA0400 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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![]() | TRANSPORT PROTEIN / Na/Ca exchanger / sodium calcium exchanger | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Function / homology | ![]() relaxation of smooth muscle / calcium:sodium antiporter activity / vascular associated smooth muscle contraction / regulation of cell communication by electrical coupling / negative regulation of protein serine/threonine kinase activity / calcium ion export / membrane depolarization during cardiac muscle cell action potential / sodium ion export across plasma membrane / regulation of the force of heart contraction / cell communication by electrical coupling involved in cardiac conduction ...relaxation of smooth muscle / calcium:sodium antiporter activity / vascular associated smooth muscle contraction / regulation of cell communication by electrical coupling / negative regulation of protein serine/threonine kinase activity / calcium ion export / membrane depolarization during cardiac muscle cell action potential / sodium ion export across plasma membrane / regulation of the force of heart contraction / cell communication by electrical coupling involved in cardiac conduction / intracellular sodium ion homeostasis / sodium ion import across plasma membrane / calcium ion import / calcium ion transport into cytosol / Sodium/Calcium exchangers / cardiac muscle cell development / regulation of cardiac muscle contraction by calcium ion signaling / Reduction of cytosolic Ca++ levels / ankyrin binding / relaxation of cardiac muscle / calcium ion transmembrane import into cytosol / negative regulation of cytosolic calcium ion concentration / cellular response to caffeine / positive regulation of the force of heart contraction / calcium ion import across plasma membrane / intercalated disc / regulation of cardiac conduction / positive regulation of bone mineralization / regulation of cardiac muscle contraction by regulation of the release of sequestered calcium ion / calcium ion homeostasis / Ion homeostasis / cytoskeletal protein binding / monoatomic ion transport / cardiac muscle contraction / muscle contraction / axon terminus / response to muscle stretch / T-tubule / sodium ion transmembrane transport / regulation of heart rate / cell periphery / cellular response to reactive oxygen species / sarcolemma / calcium ion transmembrane transport / Z disc / intracellular calcium ion homeostasis / regulation of gene expression / transmembrane transporter binding / postsynapse / calmodulin binding / postsynaptic density / axon / neuronal cell body / synapse / dendrite / calcium ion binding / nucleoplasm / plasma membrane Similarity search - Function | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Biological species | ![]() ![]() ![]() | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Method | ELECTRON MICROSCOPY / single particle reconstruction / cryo EM / Resolution: 2.9 Å | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
![]() | Xue, J. / Jiang, Y. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Funding support | ![]()
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![]() | ![]() Title: Structural mechanisms of PIP activation and SEA0400 inhibition in human cardiac sodium-calcium exchanger NCX1. Authors: Jing Xue / Weizhong Zeng / Scott John / Nicole Attiq / Michela Ottolia / Youxing Jiang / ![]() Abstract: Na/Ca exchangers (NCXs) transport Ca across the plasma membrane in exchange for Na and play a vital role in maintaining cellular Ca homeostasis. Our previous structural study of human cardiac NCX1 ...Na/Ca exchangers (NCXs) transport Ca across the plasma membrane in exchange for Na and play a vital role in maintaining cellular Ca homeostasis. Our previous structural study of human cardiac NCX1 (HsNCX1) reveals the overall architecture of the eukaryotic exchanger and the formation of the inactivation assembly by the intracellular regulatory domain that underlies the cytosolic Na-dependent inactivation and Ca activation of NCX1. Here, we present the cryo-EM structures of HsNCX1 in complex with a physiological activator phosphatidylinositol 4,5-bisphosphate (PIP), or pharmacological inhibitor SEA0400, that enhances the inactivation of the exchanger. We demonstrate that PIP binding stimulates NCX1 activity by inducing a conformational change at the interface between the transmembrane (TM) and cytosolic domains that destabilizes the inactivation assembly. In contrast, SEA0400 binding in the TM domain of NCX1 stabilizes the exchanger in an inward-facing conformation that facilitates the formation of the inactivation assembly, thereby promoting the Na-dependent inactivation of NCX1. Thus, this study reveals the structural basis of PIP activation and SEA0400 inhibition of NCX1 and provides some mechanistic understandings of cellular regulation and pharmacology of NCX family proteins. #1: Journal: bioRxiv / Year: 2025 Title: Structural mechanisms of PIP activation and SEA0400 inhibition in human cardiac sodium-calcium exchanger NCX1. Authors: Jing Xue / Weizhong Zeng / Scott John / Nicole Attiq / Michela Ottolia / Youxing Jiang / ![]() Abstract: Na/Ca exchangers (NCXs) transport Ca across the plasma membrane in exchange for Na and play a vital role in maintaining cellular Ca homeostasis. Our previous structural study of human cardiac NCX1 ...Na/Ca exchangers (NCXs) transport Ca across the plasma membrane in exchange for Na and play a vital role in maintaining cellular Ca homeostasis. Our previous structural study of human cardiac NCX1 (HsNCX1) reveals the overall architecture of the eukaryotic exchanger and the formation of the inactivation assembly by the intracellular regulatory domain that underlies the cytosolic Na-dependent inactivation and Ca activation of NCX1. Here we present the cryo-EM structures of HsNCX1 in complex with a physiological activator phosphatidylinositol 4,5-bisphosphate (PIP), or pharmacological inhibitor SEA0400 that enhances the inactivation of the exchanger. We demonstrate that PIP binding stimulates NCX1 activity by inducing a conformational change at the interface between the TM and cytosolic domains that destabilizes the inactivation assembly. In contrast, SEA0400 binding in the TM domain of NCX1 stabilizes the exchanger in an inward-facing conformation that facilitates the formation of the inactivation assembly, thereby promoting the Na-dependent inactivation of NCX1. Thus, this study reveals the structural basis of PIP activation and SEA0400 inhibition of NCX1 and provides some mechanistic understandings of cellular regulation and pharmacology of NCX family proteins. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
History |
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Structure visualization
Structure viewer | Molecule: ![]() ![]() |
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Downloads & links
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Download
PDBx/mmCIF format | ![]() | 198.1 KB | Display | ![]() |
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PDB format | ![]() | 146.5 KB | Display | ![]() |
PDBx/mmJSON format | ![]() | Tree view | ![]() | |
Others | ![]() |
-Validation report
Arichive directory | ![]() ![]() | HTTPS FTP |
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-Related structure data
Related structure data | ![]() 40456MC ![]() 9iv8C 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
-Protein , 1 types, 1 molecules A
#1: Protein | Mass: 109181.070 Da / Num. of mol.: 1 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() |
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-Antibody , 2 types, 2 molecules LH
#2: Antibody | Mass: 21740.082 Da / Num. of mol.: 1 / Source method: isolated from a natural source / Source: (natural) ![]() ![]() |
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#3: Antibody | Mass: 26435.598 Da / Num. of mol.: 1 / Source method: isolated from a natural source / Source: (natural) ![]() ![]() |
-Non-polymers , 4 types, 11 molecules 






#4: Chemical | ChemComp-EKY / | ||||
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#5: Chemical | ChemComp-CA / #6: Chemical | #7: Water | ChemComp-HOH / | |
-Details
Has ligand of interest | Y |
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Has protein modification | Y |
-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
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Source (natural) |
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Source (recombinant) | Organism: ![]() | ||||||||||||||||||||||||
Buffer solution | pH: 7.4 | ||||||||||||||||||||||||
Specimen | Embedding applied: NO / Shadowing applied: NO / Staining applied: NO / Vitrification applied: YES | ||||||||||||||||||||||||
Specimen support | Grid material: GOLD / Grid mesh size: 300 divisions/in. / Grid type: Quantifoil R1.2/1.3 | ||||||||||||||||||||||||
Vitrification | Instrument: FEI VITROBOT MARK IV / Cryogen name: ETHANE |
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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 defocus max: 2000 nm / Nominal defocus min: 1000 nm |
Image recording | Electron dose: 60 e/Å2 / Film or detector model: GATAN K3 BIOQUANTUM (6k x 4k) |
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Processing
Software | Name: PHENIX / Version: 1.19.2_4158: / Classification: refinement | ||||||||||||||||||||||||
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EM software | Name: PHENIX / Category: model refinement | ||||||||||||||||||||||||
CTF correction | Type: PHASE FLIPPING AND AMPLITUDE CORRECTION | ||||||||||||||||||||||||
3D reconstruction | Resolution: 2.9 Å / Resolution method: FSC 0.143 CUT-OFF / Num. of particles: 368227 / Symmetry type: POINT | ||||||||||||||||||||||||
Refine LS restraints |
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