Colocalization of Pak with p47^phox in fMLF-stimulated macrophage-like cells. HL60 cells differentiated with phorbol ester to a macrophage-like phenotype were incubated with buffer (—) or 1 μM fMLF (1 min). Fixed and permeabilized cells were incubated with anti-Pak and anti-p47^phox antibodies and visualized using confocal microscopy. A representative image from 2 independent experiments is shown.