Functional Interactions between BK_Caα-Subunit and Annexin A5: Implications in Apoptosis

Figure 5

Proposed model to account for ANXA5/α interaction before and during apoptosis. During resting conditions, intracellular ANXA5 interacts with α and this partnership maintains the relatively low sensitivity to of α channels. Thus, ANXA5 has an inhibitory effect on α channel activity and restricts K⁺ efflux. During serum deprivation, increases and the channel begins to activate [6, 7] and ANXA5, which is associated with the phosphatidylserine, flips to the outer membrane leaflet, resulting in the physical uncoupling of α/ANXA5 interaction and a consequent increase in Ca²⁺ sensitivity. This augments channel activity further and results in an amplified K⁺ efflux and accelerates AVD, caspase activation, and cell death.