sentence: The proapoptotic proteins initiate apoptosis by the permeabilization of the outer mitochondrial membrane which results in the release of apoptogenic factors into the cytosol ( Delbridge & Strasser , 2015 ; Doerflinger , Glab & Puthalakath , 2015 ; Li & Dewson , 2015 ; Lopez & Tait , 2015 ) .