[English] 日本語
Yorodumi
- EMDB-73048: Human type 2 IP3 receptor apo state consensus map -

+
Open data


ID or keywords:

Loading...

-
Basic information

Entry
Database: EMDB / ID: EMD-73048
TitleHuman type 2 IP3 receptor apo state consensus map
Map data
Sample
  • Complex: Inositol 1,4,5-trisphosphate receptor type 2
KeywordsInositol 1 / 4 / 5-triphosphate / IP3 / receptor / calcium channel / type-2 / IP3R / IP3R-2 / ITPR2 / TRANSPORT PROTEIN
Biological speciesHomo sapiens (human)
Methodsingle particle reconstruction / cryo EM / Resolution: 2.95 Å
AuthorsLiu C / Lan Y / Tang Q / Karakas E
Funding support United States, 1 items
OrganizationGrant numberCountry
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)GM141251 United States
CitationJournal: Nat Commun / Year: 2026
Title: Conformational landscape and ligand-dependent clustering of the human type 2 IP receptor.
Authors: Caifeng Liu / Yu-Jing Lan / Max G Kushner / Qingyu Tang / Erkan Karakas /
Abstract: Inositol 1,4,5-trisphosphate (IP) receptors (IPRs) are tetrameric ER Ca channels that shape intracellular Ca signaling in response to IP, regulating diverse physiological processes. The structural ...Inositol 1,4,5-trisphosphate (IP) receptors (IPRs) are tetrameric ER Ca channels that shape intracellular Ca signaling in response to IP, regulating diverse physiological processes. The structural basis for subtype-specific regulation among the three subtypes (IPR-1-3) remains incompletely understood due to the lack of IPR-2 structures. Here, we report cryo-electron microscopy (cryo-EM) structures of human IPR-2 in distinct conformations in the presence and absence of IP, Ca, and ATP. These structures define the conformational landscape of IPR-2, delineate ligand-binding interactions, and reveal shared architectural features alongside isoform-specific differences. We also resolve ligand-dependent IPR-2 assemblies, identifying a conformation-dependent inter-channel interface. Live-cell imaging demonstrates that IPR-2 undergoes clustering following ligand-induced Ca release, and disruption of this interface selectively abolishes clustering without impairing channel activity. Together, these findings provide a structural framework for human IPR-2 and establish a mechanism linking ligand-dependent conformational changes to inter-channel interactions and post-activation cellular clustering.
History
DepositionOct 7, 2025-
Header (metadata) releaseJul 1, 2026-
Map releaseJul 1, 2026-
UpdateJul 1, 2026-
Current statusJul 1, 2026Processing site: RCSB / Status: Released

-
Structure visualization

Supplemental images

emd_73048.png

Downloads & links

-
Map

FileDownload / File: emd_73048.map.gz / Format: CCP4 / Size: 512 MB / Type: IMAGE STORED AS FLOATING POINT NUMBER (4 BYTES)
Projections & slices

Image control

Size
Brightness
Contrast
Others
AxesZ (Sec.)Y (Row.)X (Col.)
0.82 Å/pix.
x 512 pix.
= 420.864 Å		0.82 Å/pix.
x 512 pix.
= 420.864 Å		0.82 Å/pix.
x 512 pix.
= 420.864 Å

Surface

Projections

Slices (1/3)

Slices (1/2)

Slices (2/3)

Images are generated by Spider.

Voxel sizeX=Y=Z: 0.822 Å
Density

Histogram

Histogram (log scale)
Contour LevelBy AUTHOR: 0.04
Minimum - Maximum-0.27667576 - 0.4074083
Average (Standard dev.)0.0002937358 (±0.009534979)
SymmetrySpace group: 1
Details

EMDB XML:

Map geometry
Axis orderXYZ
Origin000
Dimensions512512512
Spacing512512512
CellA=B=C: 420.864 Å
α=β=γ: 90.0 °

-
Supplemental data

-
Additional map: Unsharpened Map

Fileemd_73048_additional_1.map
AnnotationUnsharpened Map
Projections & Slices
AxesZYX

Projections

Slices (1/2)
Density Histograms

Histogram

Histogram (log scale)

-
Half map: #1

Fileemd_73048_half_map_1.map
Projections & Slices
AxesZYX

Projections

Slices (1/2)
Density Histograms

Histogram

Histogram (log scale)

-
Half map: #2

Fileemd_73048_half_map_2.map
Projections & Slices
AxesZYX

Projections

Slices (1/2)
Density Histograms

Histogram

Histogram (log scale)

-
Sample components

-
Entire : Inositol 1,4,5-trisphosphate receptor type 2

EntireName: Inositol 1,4,5-trisphosphate receptor type 2
Components
  • Complex: Inositol 1,4,5-trisphosphate receptor type 2

-
Supramolecule #1: Inositol 1,4,5-trisphosphate receptor type 2

SupramoleculeName: Inositol 1,4,5-trisphosphate receptor type 2 / type: complex / ID: 1 / Parent: 0 / Macromolecule list: #1
Details: Protein was reconstituted in MSP1E3D1/DOPC nanodiscs
Source (natural)Organism: Homo sapiens (human)
Molecular weightTheoretical: 1.2 MDa

-
Experimental details

-
Structure determination

Methodcryo EM
Processingsingle particle reconstruction
Aggregation stateparticle

-
Sample preparation

Concentration2.5 mg/mL
BufferpH: 8
Component:
ConcentrationFormulaName
0.2 MNaClSodium Chloride
0.02 MTris-HClTris-HCl buffer
0.005 MEDTAEDTA
0.002 MDTTDTT
0.025 %FC-8fluorinated Fos-Choline-8

Details: 200 mM NaCl, 20 mM Tris-HCl pH 8.0, 5 mM EDTA pH 8.0, 2 mM DTT, 0.025% fluorinated Fos-Choline-8
GridModel: Quantifoil R1.2/1.3 / Material: COPPER / Mesh: 300 / Support film - Material: CARBON / Support film - topology: HOLEY
VitrificationCryogen name: ETHANE / Chamber humidity: 100 % / Chamber temperature: 281 K / Instrument: FEI VITROBOT MARK IV
Details: PELCO 595 filter paper (Ted Pella, prod. no. 47000-100) was used for vitrification..
DetailsThe sample was reconstituted in MSP1E3D1/DOPC nanodiscs

-
Electron microscopy

MicroscopeTFS KRIOS
Image recordingFilm or detector model: GATAN K3 BIOQUANTUM (6k x 4k) / Number grids imaged: 1 / Number real images: 11634 / Average electron dose: 54.7 e/Å2
Electron beamAcceleration voltage: 300 kV / Electron source: FIELD EMISSION GUN
Electron opticsIllumination mode: FLOOD BEAM / Imaging mode: BRIGHT FIELD / Cs: 2.7 mm / Nominal defocus max: 2.0 µm / Nominal defocus min: 0.8 µm / Nominal magnification: 105000
Sample stageSpecimen holder model: FEI TITAN KRIOS AUTOGRID HOLDER / Cooling holder cryogen: NITROGEN
Experimental equipment
Model: Titan Krios / Image courtesy: FEI Company

+
Image processing

CTF correctionSoftware - Name: cryoSPARC / Type: PHASE FLIPPING AND AMPLITUDE CORRECTION
Startup modelType of model: NONE
Final reconstructionResolution.type: BY AUTHOR / Resolution: 2.95 Å / Resolution method: FSC 0.143 CUT-OFF / Software - Name: cryoSPARC / Number images used: 131003
Initial angle assignmentType: MAXIMUM LIKELIHOOD / Software - Name: cryoSPARC
Final angle assignmentType: MAXIMUM LIKELIHOOD / Software - Name: cryoSPARC
Final 3D classificationNumber classes: 4 / Software - Name: cryoSPARC
FSC plot (resolution estimation)

-
Atomic model buiding 1

RefinementSpace: REAL / Protocol: FLEXIBLE FIT

+
About Yorodumi

-
News

-
Feb 9, 2022. New format data for meta-information of EMDB entries

New format data for meta-information of EMDB entries

  • Version 3 of the EMDB header file is now the official format.
  • The previous official version 1.9 will be removed from the archive.

Related info.:EMDB header

External links:wwPDB to switch to version 3 of the EMDB data model

-
Aug 12, 2020. Covid-19 info

Covid-19 info

URL: https://pdbj.org/emnavi/covid19.php

New page: Covid-19 featured information page in EM Navigator.

Related info.:Covid-19 info / Mar 5, 2020. Novel coronavirus structure data

+
Mar 5, 2020. Novel coronavirus structure data

Novel coronavirus structure data

Related info.:Yorodumi Speices / Aug 12, 2020. Covid-19 info

External links:COVID-19 featured content - PDBj / Molecule of the Month (242)：Coronavirus Proteases

+
Jan 31, 2019. EMDB accession codes are about to change! (news from PDBe EMDB page)

EMDB accession codes are about to change! (news from PDBe EMDB page)

  • The allocation of 4 digits for EMDB accession codes will soon come to an end. Whilst these codes will remain in use, new EMDB accession codes will include an additional digit and will expand incrementally as the available range of codes is exhausted. The current 4-digit format prefixed with “EMD-” (i.e. EMD-XXXX) will advance to a 5-digit format (i.e. EMD-XXXXX), and so on. It is currently estimated that the 4-digit codes will be depleted around Spring 2019, at which point the 5-digit format will come into force.
  • The EM Navigator/Yorodumi systems omit the EMD- prefix.

Related info.:Q: What is EMD? / ID/Accession-code notation in Yorodumi/EM Navigator

External links:EMDB Accession Codes are Changing Soon! / Contact to PDBj

+
Jul 12, 2017. Major update of PDB

Major update of PDB

  • wwPDB released updated PDB data conforming to the new PDBx/mmCIF dictionary.
  • This is a major update changing the version number from 4 to 5, and with Remediation, in which all the entries are updated.
  • In this update, many items about electron microscopy experimental information are reorganized (e.g. em_software).
  • Now, EM Navigator and Yorodumi are based on the updated data.

External links:wwPDB Remediation / Enriched Model Files Conforming to OneDep Data Standards Now Available in the PDB FTP Archive

-
Yorodumi

Thousand views of thousand structures

  • Yorodumi is a browser for structure data from EMDB, PDB, SASBDB, etc.
  • This page is also the successor to EM Navigator detail page, and also detail information page/front-end page for Omokage search.
  • The word "yorodu" (or yorozu) is an old Japanese word meaning "ten thousand". "mi" (miru) is to see.

Related info.:EMDB / PDB / SASBDB / Comparison of 3 databanks / Yorodumi Search / Aug 31, 2016. New EM Navigator & Yorodumi / Yorodumi Papers / Jmol/JSmol / Function and homology information / Changes in new EM Navigator and Yorodumi

Read more