Fig. 10. The regulation of phagosomal pH is aberrant in cells overexpressing DN Rab7. Control cells (closed circles, X4) and cells overexpressing DN Rab7 (open circles, 7TN) were pulsed for 10 minutes with FITC-labeled E. coli, washed and then chased to various time points in growth medium without bacteria. The internalized FITC-bacteria were used as a pH-sensitive probe to determine the pH of the phagosomes in vivo (see Materials and Methods). Values are means ± s.e.m.; n=4 for X4 and n=6 for 7TN. P<0.05 for 15, 30, 45 and 90 minute time points.