Departure gate of acidic Ca 2+ confirmed

More potent, but less known than IP 3 that liberates Ca 2+ from the ER , NAADP releases Ca 2+ from acidic stores. The notion that TPC channels mediate this Ca 2+ release was questioned recently by studies suggesting that TPC s are rather PI (3,5)P 2 ‐activated Na + channels. Ruas et al (2015) now partially reconcile these views by showing that TPC s significantly conduct both cations and confirm their activation by both NAADP and PI (3,5)P 2 . They attribute the failure of others to observe TPC ‐dependent NAADP ‐induced Ca 2+ release in vivo to inadequate mouse models that retain partial TPC function.