A newly characterized calcium-activated chloride channel has been implicated in the immune system of Drosophila, shedding light on an enigmatic family of transmembrane proteins that are ubiquitous in nature.
Ion conduction in the calcium-activated chloride channel TMEM16A is directly regulated by calcium, which binds to a site close to the pore thereby shaping the electrostatics at its intracellular entrance.
Single-particle cryo-EM and electrophysiology studies of the chloride channel TMEM16A reveals the structural basis for anion conduction and uncover its relationship to lipid scramblases of the same family.
Structures of a TMEM16 phospholipid scramblase reveal that its Ca2+-dependent activation entails global conformational changes and how these rearrangements affect the membrane to enable transbilayer lipid transfer.
The amino acids that are necessary for phospholipid scrambling by ANO6/TMEM16F can, via domain swapping, confer scrambling activity to the chloride ion channel ANO1 that normally does not scramble phospholipids.