Fig. 9.

Effect of caspase inhibitors on proteolysis of tau. A, Total protein extracts (25 μg) of control cells (S-K25) and apoptotic cerebellar granule cells (S-K5) in the presence or absence of various caspase inhibitors, YVAD-cho (100 μm), ZDEVD-fmk (150 μm), and ZVAD-fmk (100 μm), for 16 hr. All the inhibitors were added 2 hr before, and at the time of, apoptosis induction. The corresponding viability for each lysate was determined as reported in Materials and Methods. B, Densitometric analysis of the 17 kDa and the 50–55 kDa Tau-1 bands reported in A, expressed in densitometric units. Results are representative of at least two experiments. C, In vitro translated tau treated with bacterial extracts containing caspase-3. DEVD-cho is a specific inhibitor of caspase 3.