Fig. 7.

Aberrant F-actin distribution in phagosomes of cells impaired in phagocytosis. (A) Representative phagosomes from WT cells (first row) and the forG⁻ mutant cells (second row), rasB⁻ cells (third row), and scrA⁻ cells (fourth row). Growth-phase cells phagocytosing TRITC-labeled yeast particles were fixed and stained for F-actin with ATTO488-conjugated phalloidin. Note impaired F-actin distribution in the mutant cells and empty cups in scrA⁻ cells (fourth row) suggesting loose association with the yeast particles. (Scale bar: 2 μm.) (B) Quantification of the relative F-actin contents in the phagosomes of WT and mutant cells. Fluorescence intensities of the ATTO488 phalloidin-labeled F-actin structure along the contour lengths of phagosomes are shown (mean ± SD). The base of the phagosomes was set to 0% (n = 25 for each cell line). AU, arbitrary units.