Download MendeleyCryo-EM reveals ligand induced allostery underlying InsP3R channel gating.
Fan, G., Baker, M.R., Wang, Z., Seryshev, A.B., Ludtke, S.J., Baker, M.L., Serysheva, I.I.(2018) Cell Res 28: 1158-1170
- PubMed: 30470765
- DOI: https://doi.org/10.1038/s41422-018-0108-5
- Primary Citation of Related Structures:
6MU1, 6MU2 - PubMed Abstract:
Inositol-1,4,5-trisphosphate receptors (InsP 3 Rs) are cation channels that mobilize Ca 2+ from intracellular stores in response to a wide range of cellular stimuli. The paradigm of InsP 3 R activation is the coupled interplay between binding of InsP 3 and Ca 2+ that switches the ion conduction pathway between closed and open states to enable the passage of Ca 2+ through the channel. However, the molecular mechanism of how the receptor senses and decodes ligand-binding signals into gating motion remains unknown. Here, we present the electron cryo-microscopy structure of InsP 3 R1 from rat cerebellum determined to 4.1 Å resolution in the presence of activating concentrations of Ca 2+ and adenophostin A (AdA), a structural mimetic of InsP 3 and the most potent known agonist of the channel. Comparison with the 3.9 Å-resolution structure of InsP 3 R1 in the Apo-state, also reported herein, reveals the binding arrangement of AdA in the tetrameric channel assembly and striking ligand-induced conformational rearrangements within cytoplasmic domains coupled to the dilation of a hydrophobic constriction at the gate. Together, our results provide critical insights into the mechanistic principles by which ligand-binding allosterically gates InsP 3 R channel.
- Department of Biochemistry and Molecular Biology, Structural Biology Imaging Center, McGovern Medical School at The University of Texas Health Science Center at Houston, 6431 Fannin Street, Houston, TX, 77030, USA.
Organizational Affiliation:
