Bcl-xL Blocks a Mitochondrial Inner Membrane Channel and Prevents Ca2+ Overload-Mediated Cell Death
Figure 4
Bcl-xL blocks the Ca2+-induced MCC activation in isolated mitoplasts.
Mitoplasts were prepared and single channel activity was recorded as indicated in Materials and Methods. a) Induction of MCC activity following increase in Ca2+ concentration (upper bar) in SH-SY5Y/Neo cells. b) Inhibition of Ca2+-induced MCC activation by Ca2+ chelation in SH-SY5Y/Neo. EGTA 20 mM was added after Ca2+ stimulation (upper bars). c) Same protocol as in a) performed in mitoplasts obtained from SH-SY5Y/Bcl-xL cells. No channel activity can be observed after 10 µM Ca2+ addition despite the channel was present in the patch (supplemental material figure S1). d) Percentage of patches where a rise in Ca2+ (10 µM) induced MCC activity provided that the channel was present in the patch. This was tested at the end of the experiment as indicated in Material and Methods. Data represent the percentage of patches where the channel was opened for SH-SY5Y/Neo (n = 10) and SH-SY5Y/Bcl-xL (n = 13) cells.