Figure 4.

Cardiolipin dependence is mainly conferred by N/C-Bid. (A) Liposomes containing 0 or 7% mol cardiolipin were generated and dextran release assays were performed with different activators of Bax, namely, N/C-Bid, Bid BH3 peptide, or Bim BH3 peptide. Among those, only N/C-Bid showed cardiolipin dependence. The peptides alone did not permeabilize liposomes (data not shown). Data shown are representative of four experiments. (B) OG-oligomerized Bax (OG-Bax) permeabilized liposomes in the absence of cardiolipin to a significant degree. Data shown are representative of two experiments. (C) Mtch2, a reported Bid-binding protein in the MOM (Grinberg et al., 2005), was detected in ReOMVs but not in ExOMVs. ReOMVs and ExOMVs were loaded on to a SDS-PAGE gel, and proteins were stained by Coomassie Blue. Predominant bands ∼30-kDa were subjected to trypsin digestion, and the proteins were identified by mass spectrometry. Note that Xenopus VDAC (xVDAC) variants xVDAC1 and 2 do not correspond to the mammalian VDAC isoforms.