Intracellular Ca2+ channels - A growing community

► Regulated opening of Ca2+ channels underlies most intracellular Ca2+ signalling. ► Endoplasmic reticulum is the major Ca2+ store, bit other organelles also contribute. ► IP3 and ryanodine receptors are the most widely expressed intracellular Ca2+ channels. ► Additional Ca2+ channels in the ER or other organelles can also evoke Ca2+ signals. ► Interactions between Ca2+ channels shape the resulting Ca2+ signal and cellular response.