Fig. 4. Loss of microtubule-binding activity does not alter the effects of tau on PDGF-induced actin reorganization. 3T3 cells were transfected with S262D/S356D mutant tau, stimulated with PDGF, and double-labeled as described in Fig. 2 (phalloidin-Alexa594 in A,B,C and anti-tau in D,E,F). The mutated tau exhibited a diffuse cytoplasmic distribution due to its loss of microtubule binding. Bar, 10 µm.