Phosphoinositide-specific phospholipase C beta 1 expression is not linked to nerve growth factor-induced differentiation, cell survival or cell cyclecontrol in PC12 rat pheocromocytoma cells

Recent reports have highlighted that phosphoinositicle-specific phospholipa se C beta1 expression is linked to neuronal differentiation in different ex perimental models. We sought to determine whether or not this is also true for nerve growth factor (NGF)-induced neuronal differentiation of rat PC12 cells. However, we did not find differences in the expression of both the f orms of phosphoinositicle-specific phospholipase C beta1 (a and b) during s ympathetic differentiation of these cells. Also, PC12 cell clones stably ov erexpressing phosphoinositicle-specific phospholipase CPI were not more sus ceptible to the differentiating effect of NCF. Furthermore, since it is wel l established that phosphoinositide-specific phospholipase C beta1 affects cell proliferation, we investigated whether or not PC12 cell clones stably overexpressing phosphoinositicle-specific phospholipase C beta1 showed diff erences in survival to serum deprivation and cell cycle, when compared to w ild type cells. Nevertheless, we did not find any differences in these para meters between wild type cells and the overexpressing clones. Interestingly , in PC12 cells the overexpressed phosphoinositide-specific phospholipase C beta1 did not localize to the nucleus, but by immunofluorescence analysis, was detected in the cytoplasm. Therefore, our findings may represent anoth er important clue to the fact that only when it is located within the nucle us phosphoinositide-specific phospholipase C beta1 is able to influence cel l proliferation. (C) 2001 Wiley-Liss, Inc.