Changes in microtubule-associated tau protein in human neuroblastoma cells after phencyclidine

1. A human neuroblastoma cell line, SH-SY5Y, was used to study the effects of phencyclidine (PCP) on microtubule-associated tau protein, which acts in vivo chiefly to induce the assembly of tubulin and in vitro to promote microtubule polymerization. 2. PCP (1.0 mM) decreased tau protein (50 kD) in the cytoplasmic (supernatant) fraction as well as in the membrane (pellet) fraction. 3. These changes in tau protein were accompanied by decreases of 30-95% in cell number after concentrations of PCP, 0.25-1.0 mM, respectively. 4. After 0.5 mM PCP cytoplasmic and membrane fractions of SH-SY5Y cells showed 100 and 84% increases in total protein, respectively.