Download MendeleyGating machinery of InsP3R channels revealed by electron cryomicroscopy.
Fan, G., Baker, M.L., Wang, Z., Baker, M.R., Sinyagovskiy, P.A., Chiu, W., Ludtke, S.J., Serysheva, I.I.(2015) Nature 527: 336-341
- PubMed: 26458101
- DOI: https://doi.org/10.1038/nature15249
- Primary Citation of Related Structures:
3JAV - PubMed 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.
Organizational Affiliation:
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.
