EMD-6369
Structure of full-length IP3R1 channel in the apo-state determined by single particle cryo-EM
EMD-6369
Single-particle4.7 Å
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Map released: 07/10/2015
Last modified: 09/12/2015
Sample Organism:
Rattus norvegicus
Sample: Inositol 1,4,5-trisphosphate receptor, type 1
Fitted models: 3jav (Avg. Q-score: 0.219)
Deposition Authors: Fan G, Baker ML, Wang Z
,
Baker MR,
Sinyagovskiy PA,
Chiu W,
Ludtke SJ
,
Serysheva II
Sample: Inositol 1,4,5-trisphosphate receptor, type 1
Fitted models: 3jav (Avg. Q-score: 0.219)
Deposition Authors: Fan G, Baker ML, Wang Z
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Gating machinery of InsP3R channels revealed by electron cryomicroscopy.
Fan G,
Baker ML,
Wang Z
,
Baker MR,
Sinyagovskiy PA,
Chiu W,
Ludtke SJ
,
Serysheva II
(2015) Nature , 527 , 336 - 341
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(2015) Nature , 527 , 336 - 341
Abstract:
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 Å) 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 ∼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 α-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.
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 Å) 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 ∼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 α-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.