Orai channels mediate store-operated Ca 2+ signals crucial in regulating transcription in
many cell types, and implicated in numerous immunological and inflammatory disorders.
Despite their central importance, controversy surrounds the basic subunit structure of Orai
channels, with several biochemical and biophysical studies suggesting a tetrameric
structure yet crystallographic evidence indicating a hexamer. We systematically investigated
the subunit configuration of the functional Orai1 channel, generating a series of tdTomato …