Cover photograph (Copyright © 2001, American Society for Microbiology. All rights reserved.): Active RhoG increases lysosome velocity in COS-7 cells. Lysosomes of COS-7 cells expressing GFP-RhoG_G12V were stained with LysoTracker. This picture represents a merged stack of time lapse images (acquired every 10 s for 10 min) in which lysosomes moving in a directed fashion appear as linear series of dots (arrows) whereas randomly moving lysosomes appear as spot clusters (circles). Image acquisition and lysosome tracking were performed at the Integrated Imaging Facility of the laboratory. (See related article on p. 8022.)