Publication Date:
2015-10-13
Description:
Inositol-1,4,5-trisphosphate receptors (InsP3Rs) are ubiquitous ion channels responsible for cytosolic Ca(2+) signalling and essential for a broad array of cellular processes ranging from contraction to secretion, and from proliferation to cell death. Despite decades of research on InsP3Rs, a mechanistic understanding of their structure-function relationship is lacking. Here we present the first, to our knowledge, near-atomic (4.7 A) resolution electron cryomicroscopy structure of the tetrameric mammalian type 1 InsP3R channel in its apo-state. At this resolution, we are able to trace unambiguously approximately 85% of the protein backbone, allowing us to identify the structural elements involved in gating and modulation of this 1.3-megadalton channel. Although the central Ca(2+)-conduction pathway is similar to other ion channels, including the closely related ryanodine receptor, the cytosolic carboxy termini are uniquely arranged in a left-handed alpha-helical bundle, directly interacting with the amino-terminal domains of adjacent subunits. This configuration suggests a molecular mechanism for allosteric regulation of channel gating by intracellular signals.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Fan, Guizhen -- Baker, Matthew L -- Wang, Zhao -- Baker, Mariah R -- Sinyagovskiy, Pavel A -- Chiu, Wah -- Ludtke, Steven J -- Serysheva, Irina I -- P41 GM103832/GM/NIGMS NIH HHS/ -- P41GM103832/GM/NIGMS NIH HHS/ -- R01 GM072804/GM/NIGMS NIH HHS/ -- R01 GM079429/GM/NIGMS NIH HHS/ -- R01 GM080139/GM/NIGMS NIH HHS/ -- R01GM072804/GM/NIGMS NIH HHS/ -- R01GM079429/GM/NIGMS NIH HHS/ -- R01GM080139/GM/NIGMS NIH HHS/ -- R21 AR063255/AR/NIAMS NIH HHS/ -- R21 GM100229/GM/NIGMS NIH HHS/ -- R21AR063255/AR/NIAMS NIH HHS/ -- R21GM100229/GM/NIGMS NIH HHS/ -- S10 OD016279/OD/NIH HHS/ -- S10OD016279/OD/NIH HHS/ -- England -- Nature. 2015 Nov 19;527(7578):336-41. doi: 10.1038/nature15249. Epub 2015 Oct 12.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry and Molecular Biology, Structural Biology Imaging Center, The University of Texas Medical School at Houston, 6431 Fannin Street, Houston, Texas 77030, USA. ; National Center for Macromolecular Imaging, Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77030, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26458101" target="_blank"〉PubMed〈/a〉
Keywords:
Allosteric Regulation
;
Animals
;
Apoproteins/chemistry/metabolism/ultrastructure
;
Calcium/metabolism
;
Calcium Signaling
;
*Cryoelectron Microscopy
;
Cytosol/chemistry/metabolism
;
Inositol 1,4,5-Trisphosphate Receptors/chemistry/*metabolism/*ultrastructure
;
Ion Channel Gating
;
Models, Molecular
;
Protein Folding
;
Protein Structure, Quaternary
;
Protein Structure, Secondary
;
Protein Structure, Tertiary
;
Protein Subunits/chemistry/metabolism
;
Rats
;
Ryanodine Receptor Calcium Release Channel/chemistry/metabolism
Print ISSN:
0028-0836
Electronic ISSN:
1476-4687
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
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