The process of apoptosis is not only regulated by molecular gens but it is also regulated by cellular ionic homeostasis especially K+ homeostasis in the cell. In the past decade, molecular mechanisms of ionic regulation of apoptosis have been extensively investigated. The ionic mechanism of apoptosis are involves Ca2+ influx and accumulation of intracellular Ca2+ is convincing evidence to excessive K+ efflux resulting in early steps in apoptosis. The BK channels play a critical role in mediating the K+ efflux linked with apoptotic cell shrinkage. Mitochondria-associated ER membranes (MAMs) control Ca2+ influx between ER and mitochondria. The BKα subunits are localized in the inner mitochondrial and ER membrane and directly interact with other BK channel associated proteins (BKAPs) like, IP3R-1, calreticulin at the ER face of the MAMs, and the molecular chaperone grp78, which bridges the IP3R-1 with voltage-dependent anion channel (VDAC-1) of the outer mitochondrial membrane (OMM). The present chapter clearly depicts that how BK channels are associated with BKAPs and how they are involved in apoptosis through regulation of K+ efflux.
Part of the book: Current Understanding of Apoptosis