Ceramide-induced translocation of protein kinase C zeta in primary cultures of astrocytes.

The present research was undertaken to study the possible involvement of the atypical protein kinase C (PKC) zeta in ceramide signal transduction in primary cultures of rat astrocytes. As shown by Western blot analysis, translocation of immunoreactive PKCzeta to the particulate fraction occurred upon exposure of astrocytes to cell-permeable ceramide analogs or to exogenous sphingomyelinase. The particulate fraction may correspond to a perinuclear area, as indicated by immunocytochemical techniques. Furthermore, treatment of cells with N-octanoylsphingosine led to an increased phosphorylation of PKCzeta. Results thus show that stimulation of PKCzeta may be one of the intracellular events triggered by activation of the sphingomyelin pathway.