Figure 2.

BAX moves from the cytosol to the mitochondrial outer membrane during apoptosis. A cell engineered to express both BAX linked to green fluorescent protein (BAX–GFP) and a red fluorescent protein (RFP) that localizes to mitochondria was induced to undergo apoptosis. BAX (green) moves onto the mitochondria (red), revealed as the development of a yellow signal (i.e., merging of red and green emissions) over time. The first image was taken several hours after the initial stress. (Courtesy of Dr. Stephen Tait, University of Glasgow, Scotland, United Kingdom).