Orai channels: key players in Ca homeostasis.

Maintaining a precise calcium (Ca) balance is vital for cellular survival. The most prominent pathway to shuttle Ca into cells is the Ca release activated Ca (CRAC) channel. Orai proteins are indispensable players in this central mechanism of Ca entry. This short review traces the latest articles published in the field of CRAC channel signalling with a focus on the structure of the pore-forming Orai proteins, the propagation of the binding signal from STIM1 through the channel to the central pore and their role in human health and disease.