title: Structure of the type 1 inositol 1,4,5-trisphosphate receptor revealed by electron cryomicroscopy.
abstract: 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.
authors.affiliation: Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030, USA. irinas@bcm.tmc.edu
authors.forename: Irina I
authors.initials: II
authors.lastname: Serysheva
authors.forename: Dan J
authors.initials: DJ
authors.lastname: Bare
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Ludtke
authors.forename: Claudia S
authors.initials: CS
authors.lastname: Kettlun
authors.forename: Wah
authors.initials: W
authors.lastname: Chiu
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Mignery
mesh_terms: D000818:Animals; D015220:Calcium Channels / Q000737:chemistry* / Q000648:ultrastructure; D002417:Cattle; D020285:Cryoelectron Microscopy; D018360:Crystallography, X-Ray; D004591:Electrophoresis, Polyacrylamide Gel; D004594:Electrophysiology; D004721:Endoplasmic Reticulum / Q000378:metabolism; D053496:Inositol 1,4,5-Trisphosphate Receptors; D008954:Models, Biological; D011485:Protein Binding; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D018160:Receptors, Cytoplasmic and Nuclear / Q000737:chemistry* / Q000648:ultrastructure; D014965:X-Rays
chemical_list: D015220:Calcium Channels; D053496:Inositol 1,4,5-Trisphosphate Receptors; D018160:Receptors, Cytoplasmic and Nuclear