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.
Organizational Affiliation:
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.
