The SPRY domain is of unknown function. Distant homologues are domains inbutyrophilin/marenostrin/pyrin [<cite idref="PUB00005467"/>].Ca<sup>2+</sup>-release from the sarcoplasmic or endoplasmic reticulum, the intracellular Ca<sup>2+</sup> store, is mediated by the ryanodine receptor (RyR) and/or the inositol trisphosphate receptor (IP3R).
SPla/RYanodine receptor SPRY