Structure of the type 1 inositol 1,4,5-trisphosphate receptor revealed by electron cryomicroscopy.
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.
Serysheva
Irina I
II
Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030, USA. irinas@bcm.tmc.edu
Bare
Dan J
DJ
Ludtke
Steven J
SJ
Kettlun
Claudia S
CS
Chiu
Wah
W
Mignery
Gregory A
GA
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
D015220:Calcium Channels; D053496:Inositol 1,4,5-Trisphosphate Receptors; D018160:Receptors, Cytoplasmic and Nuclear