Structural titration reveals Ca²⁺-dependent conformational landscape of the IP₃ receptor.

ABSTRACT: Inositol 1,4,5-trisphosphate receptors (IP₃Rs) are endoplasmic reticulum Ca²⁺ channels whose biphasic dependence on cytosolic Ca²⁺ gives rise to Ca²⁺ oscillations that regulate fertilization, cell division and cell death. Despite the critical roles of IP₃R-mediated Ca²⁺ responses, the structural underpinnings of the biphasic Ca²⁺ dependence that underlies Ca²⁺ oscillations are incompletely understood. Here, we collect cryo-EM images of an IP₃R with Ca²⁺ concentrations spanning five orders of magnitude. Unbiased image analysis reveals that Ca²⁺ binding does not explicitly induce conformational changes but rather biases a complex conformational landscape consisting of rest

SUBMITTER: Paknejad N 

PROVIDER: S-EPMC10613215 | biostudies-literature | 2023 Oct

REPOSITORIES: biostudies-literature