Complex sentence: In healthy mammalian cells, the majority of Bax is found in the cytosol, but upon initiation of apoptotic signaling, Bid undergoes a conformation shift, and inserts into organelle membranes, primarily the outer mitochondrial membrane.
Split into simpler sentences: In healthy mammalian cells, the majority of BAX is found in the cytosol. However, upon the initiation of apoptotic signaling, BAX undergoes a conformation shift, and inserts into organelle membranes, primarily the outer mitochondrial membrane.