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

Figure 4

α channel function is modulated by its interaction with ANXA5 at different concentrations of Ca²⁺. (a) Time course showing the stimulatory effect of 30 μM CORM-2 and the sequential increase of [Ca²⁺] in the concentration range 10 nM–1 mM on α subunit channel normalized current and Va₅₀ in the control (black line), in the ANXA5 knockdown model achieved by transfection with siRNA (dark grey line), and in the ANXA5 overexpression model achieved by transfection with the DNA plasmid (light grey line). (b) Mean (± SEM) concentration-response plots displaying the stimulation effect of the sequential increase of [Ca²⁺] in the concentration range 10 nM–1 mM on α channel normalized current at the holding voltage of 60 mV in the wild type (black square and a solid black line, ), in the ANXA5 knockdown model achieved by transfection with siRNA (grey circle and a solid grey line, ), in the ANXA5 overexpression model achieved by transfection with ANXA5 DNA plasmid (light grey triangle and a solid light grey line, ), on Va₅₀ of α channels in the wild type (white square and a dashed black line, ), in the ANXA5 knockdown model achieved by transfection with siRNA (white circle and a dashed grey line, ), and in the ANXA5 overexpression model achieved by transfection with ANXA5 DNA plasmid (white triangle and a dashed light grey line, ).

(a)

(b)