Cover photograph (Copyright © 2006, American Society for Microbiology. All Rights Reserved.): MafB^-/- peritioneal exudate cells that were cultured for 5 min in monocyte colony-stimulating factor-containing medium, fixed, and stained with tetramethyl rhodamine isocyanate-conjugated phalloidin (red) to reveal actin organization and anti-F4/80 fluorescein-conjugated antibody (green) to identify macrophages. MafB^-/- macrophages revealed multiple prominent and often branched protrusions. (See related article on page 6808.)