Structure of the type 1 inositol 1,4,5-trisphosphate receptor revealed by electron cryomicroscopy

J Biol Chem. 2003 Jun 13;278(24):21319-22. doi: 10.1074/jbc.C300148200. Epub 2003 Apr 24.


The three-dimensional structure of the type 1 inositol 1,4,5-trisphosphate receptor (InsP3R1) has been determined by electron cryomicroscopy and single-particle reconstruction. The receptor was immunoaffinity-purified and formed functional InsP3- and heparin-sensitive channels with a unitary conductance similar to native InsP3Rs. The channel structure exhibits the expected 4-fold symmetry and comprises two morphologically distinct regions: a large pinwheel and a smaller square. The pinwheel region has four radial curved spokes interconnected by a central core. The InsP3-binding core domain has been localized within each spoke of the pinwheel region by fitting its x-ray structure into our reconstruction. A structural mapping of the amino acid sequences to several functional domains is deduced within the structure of the InsP3R1 tetramer.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Calcium Channels / chemistry*
  • Calcium Channels / ultrastructure
  • Cattle
  • Cryoelectron Microscopy
  • Crystallography, X-Ray
  • Electrophoresis, Polyacrylamide Gel
  • Electrophysiology
  • Endoplasmic Reticulum / metabolism
  • Inositol 1,4,5-Trisphosphate Receptors
  • Models, Biological
  • Protein Binding
  • Protein Conformation
  • Protein Structure, Tertiary
  • Receptors, Cytoplasmic and Nuclear / chemistry*
  • Receptors, Cytoplasmic and Nuclear / ultrastructure
  • X-Rays


  • Calcium Channels
  • Inositol 1,4,5-Trisphosphate Receptors
  • Receptors, Cytoplasmic and Nuclear