Intracellular calcium release channels (Ryanodine receptor and Inositol 1,4,5-trisphosphate receptor) (RyR/IP3R)

Intracellular calcium stores and their release mechanisms are fundamental components of cellular signaling, primarily involving the endoplasmic reticulum (ER) and sarcoplasmic reticulum (SR). The release of sequestered calcium into the cytosol is predominantly mediated by two families of large tetrameric ion channels: the Inositol 1,4,5-trisphosphate receptors (IP3R) and the Ryanodine receptors (RyR) (StatPearls, 2023). These channels respond to various stimuli, such as second messengers or membrane depolarization, to trigger rapid increases in local calcium concentrations, which drive processes like muscle contraction, neurotransmission, and gene transcription (PubMed, PMC7271144). Dysregulation of these mechanisms, leading to pathological calcium leaks or impaired sequestration, is a hallmark of several diseases, including cardiac arrhythmias, skeletal muscle disorders, and neurodegeneration (UniProt, 2024). Therapeutic strategies often focus on stabilizing these channels or modulating their sensitivity to prevent pathological calcium overloads. For example, dantrolene is a clinically used antagonist of RyR1 employed to treat malignant hyperthermia by inhibiting uncontrolled calcium release (PubChem, CID 2952).

Other names

Intracellular calcium storesCalcium release mechanismsER/SR calcium release channelsCalcium-induced calcium release (CICR)

Modulation of the open-state probability of intracellular calcium release channels, specifically Ryanodine receptors and Inositol 1,4,5-trisphosphate receptors, to regulate the efflux of calcium ions from the endoplasmic or sarcoplasmic reticulum into the cytosol (StatPearls, 2023).