Nonfamilial interactions with antiapoptotic proteins Bcl-2 or Bcl-X_L and with proapoptotic proteins Bax or Bak. (A) The depicted protein interactions have been reported for either Bcl-2 or Bcl-X_L. (B) The depicted protein interactions have been reported for Bax or Bak. In many cells, Bax is present in a latent (inactive) conformation in the cytosol,⁵⁷  in which its C-terminal transmembrane domain is folded onto the protein.⁶⁴  Activators of Bax induce conformational changes that promote Bax's insertion into membranes of mitochondria, followed by BH3-induced oligomerization in membranes. Several proteins that modulate these steps have been reported.