Laboratory of Molecular Signalling, The Babraham Institute, Babraham, CB2 4AT, UK.
The 'bell-shaped' curve relating cytosolic Ca(2+) concentration to IP(3) receptor activation is considered important in the generation of the complex Ca(2+) signals seen inside many cells. But recent findings suggest this bimodal relationship is not always evident and may not apply to some IP(3) receptor isoforms.