Caspase-Mediated Truncation of Tau Potentiates Aggregation
Figure 3
Effect of Z-VAD-fmk and staurosporine on aggregation and truncation. (a) presents quantification of the percentage of cells containing aggregates as detected by GFP with and without pharmacological manipulation of caspase activity. (b) presents quantification of the number of aggregates per cell. Note that staurosporine significantly increased, while Z-VAD-fmk induced a detectable but nonstatistically significant decrease, the percentage of cells with aggregates as well as the number of aggregates per cell. Values represent the mean ± SEM from 3 independent experiments (*, Student’s t-test). (c) presents double immunofluorescent staining with anti-GFP and either C3 (upper images) or Tau46 (lower images) with and without treatment with Z-VAD-fmk or staurosporine as indicated. The bar represents 20 μm. Arrows indicate representative aggregates. Note that staurosporine-treated cells display stronger C3 immunoreactivity within aggregates and very weak Tau46 immunoreactivity within the cytosol. Staurosporine panels include insets from a different transfected cell to highlight that C3, but not Tau46 or GFP, is localized around the periphery of some aggregates. (d) presents quantification of immunofluorescence intensity of anti-GFP, C3 and Tau46 between aggregates and adjacent cytosolic tau in the same cells. All bars connected by lines are statistically different (; Student’s t-test); continuous lines connect values for aggregates, while dotted lines connect values for cytosol. Values represent the mean ± SEM (, Student’s t-test).
