Figure 3.

CD82 inhibits the formation of microprotrusions and microspikes and the NQE mutation breaks off the inhibition. A: Du145 transfectant cells were cultured to subconfluence and then detached from dishes. The cells were then fixed, thin-sectioned, stained, and analyzed under a transmission electron microscope, as described in Materials and Methods. The images represent the results from one out of three individual experiments. Arrows indicate the microprotrusions and asterisks indicate microvesicles. Scale bar = 2 μm. The percentages of microprotrusion-positive cells of total cells were quantified from multiple distinct sections in each transfectant and shown in the histogram on the left. A cell with more than five microprotrusions was defined as a microprotrusion-positive cell. The P values: <0.01 between Mock and wild-type and between wild-type and NQE mutant and >0.05 between Mock and NQE mutant. The numbers of microvesicle per cell section were quantified from multiple distinct sections in each transfectant and shown in the histogram on the right. The P values: <0.01 between Mock and wild-type and between wild-type and NQE mutant and >0.05 between Mock and NQE mutant. B: Du145 transfectant cells were fixed and incubated sequentially with integrin α3 mAb X8 and FITC-conjugated second Ab. The images were captured under a fluorescent microscope. Scale bar = 5 μm. The percentages of microspike-positive cells were quantified in each transfectant and shown in the histogram on the left. A cell with more than 20 microspike was defined as a microspike-positive cell. The P value <0.01 between Mock and wild-type, <0.01 between wild-type and NQE mutant, and = 0.02 between Mock and NQE mutant. The average length of microspikes was quantified in 10 cells randomly selected from each transfectant and shown in the histogram on the right. The P value <0.01 between Mock and wild-type, <0.01 between wild-type and NQE mutant, and >0.05 between Mock and NQE mutant.