Eu³⁺ detects two functionally distinct luminal Ca²⁺ binding sites in ryanodine receptors.

ABSTRACT: Ryanodine receptors (RyRs) are Ca²⁺ release channels, gated by Ca²⁺ in the cytosol and the sarcoplasmic reticulum lumen. Their regulation is impaired in certain cardiac and muscle diseases. Although a lot of data is available on the luminal Ca²⁺ regulation of RyR, its interpretation is complicated by the possibility that the divalent ions used to probe the luminal binding sites may contaminate the cytoplasmic sites by crossing the channel pore. In this study, we used Eu³⁺, an impermeable agonist of Ca²⁺ binding sites, as a probe to avoid this complication and to gain more specific information about the function of the luminal Ca²⁺ sensor. Single-channel currents were measured from skeletal muscle and cardiac RyRs (RyR1 and R

SUBMITTER: Magyar ZE 

PROVIDER: S-EPMC10502479 | biostudies-literature | 2023 Sep

REPOSITORIES: biostudies-literature