Figure 4.

MAC and rBax display similar single channel characteristics. (A) Current traces show the channel activities recorded when monomeric BaxΔC, t-Bid, or oligomeric BaxΔC (rBax) were included in the tip of the micropipette and seals were formed on giant liposomes formed without protein. No channel activities developed when the tips of the microelectrodes were loaded with buffer only (our unpublished data). (B) Histogram compares the frequency profile of recording peak conductances for MAC of apoptotic FL5.12 cells (MAC) and channels formed by rBax. The peak conductances of MAC and rBax channels were determined from amplitude histograms and shown as a function of their frequency (n = 57 and 35 independent patches displaying MAC and rBax channels, respectively). Bin width was 0.5 nS and conductances below 1.5 nS were not considered. See Materials and Methods for formation of rBax (BaxΔC oligomers formed by exposure to Triton X-100 or t-Bid).