CHARACTERIZATION OF TAU-PROTEINS IN HUMAN NEUROBLASTOMA SH-SY5Y CELL-LINE

Here we report three experimental paradigms in which tau proteins are differentially localized and expressed in human neuroblastoma cells SH -SY5Y. We found that in undifferentiated cells, tau proteins were pred ominantly localized in the nucleus. Western blot analysis of nuclear e xtracts revealed, among the others, a high molecular weight tau isofor m and evaluation of tau mRNA levels showed a single tau isoform. After differentiation, tau immunoreactivity was detected only in cytosol an d along neuritic processes. The high molecular weight tau isoform disa ppeared and an additional tau mRNA species was detected. Treatment of differentiated cells with doxorubicin or okadaic acid resulted in an i ncrease of tau immunoreactivity and in a subsequent cell loss. Our res ults indicate that both subcellular localization and pattern of expres sion of tau proteins vary depending on the developmental and functiona l state of the cells, thus suggesting different roles in cell function . (C) 1997 Elsevier Science Ireland Ltd.