Download MendeleyConformational landscape and ligand-dependent clustering of the human type 2 IP 3 receptor.
Liu, C., Lan, Y.J., Kushner, M.G., Tang, Q., Karakas, E.(2026) Nat Commun
- PubMed: 42315508 Search on PubMed
- DOI: https://doi.org/10.1038/s41467-026-74494-y
- Primary Citation Related Structures:
9YKK, 9YKY, 9YLI, 9YMZ, 9YNK, 9YNO - PubMed Abstract:
Inositol 1,4,5-trisphosphate (IP 3 ) receptors (IP 3 Rs) are tetrameric ER Ca 2+ channels that shape intracellular Ca 2+ signaling in response to IP 3 , regulating diverse physiological processes. The structural basis for subtype-specific regulation among the three subtypes (IP 3 R-1-3) remains incompletely understood due to the lack of IP 3 R-2 structures. Here, we report cryo-electron microscopy (cryo-EM) structures of human IP 3 R-2 in distinct conformations in the presence and absence of IP 3 , Ca 2+ , and ATP. These structures define the conformational landscape of IP 3 R-2, delineate ligand-binding interactions, and reveal shared architectural features alongside isoform-specific differences. We also resolve ligand-dependent IP 3 R-2 assemblies, identifying a conformation-dependent inter-channel interface. Live-cell imaging demonstrates that IP 3 R-2 undergoes clustering following ligand-induced Ca 2+ release, and disruption of this interface selectively abolishes clustering without impairing channel activity. Together, these findings provide a structural framework for human IP 3 R-2 and establish a mechanism linking ligand-dependent conformational changes to inter-channel interactions and post-activation cellular clustering.
- Department of Molecular Physiology and Biophysics, Vanderbilt University, School of Medicine, Nashville, TN, USA.
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