Fig. 5.

The temporal sequence of events leading to apoptosis in response to CK2 inhibition. We propose that inhibition of CK2 results in intracellular Ca²⁺ flux so that there is rapid loss of cytosolic Ca²⁺ with a concomitant increase in ER and mitochondrial Ca²⁺. These changes are reflected in the loss of Δψ_m within 2 h. If the cells are treated with 80 μM TBB (high CK2i), they follow a path that results in decreased total cellular Ca²⁺ and induction of the mitochondrial apoptotic pathway and cell death. If the cells are treated with 8 μM TBB (low CK2i), there is no change in total cellular Ca²⁺ and concomitant recovery of Δψ_m, with the result that cells survive