Identification of a family of calcium sensors as protein ligands of inositol trisphosphate receptor Ca~2+ release channels

摘要

The inositol trisphosphate (InsP_3) receptor (InsP_3R) is a ubiquitously expressed intracellular Ca~2+ channel that mediates complex cyto- plasmic Ca~2+ signals, regulating diverse cellular processes, include- ing synaptic plasticity. Activation of the InsP_3R channel is normally thought to require binding of InsP_3 derived from receptor-medi- ated activation of phosphatidylinositol lipid hydrolysis. Here we identify a family of neuronal Ca~2+-binding proteins as high-affinity protein agonists of the InsP_3R, which bind to the channel and activate gating in the absence of InsP_3.