Subtype-specific translocation of diacylglycerol kinase α and γ and its correlation with protein kinase C

We examined the translocation of diacylglycerol kinase (DGH) alpha and gamma fused with green fluorescent protein in Living Chinese hamster ovary K1 cells (CHO-K1) and investigated temporal and spatial correlations between DGK and protein kinase C (PKC) when both kinases are overexpressed. DGK alpha and gamma were present throughout the cytoplasm of CHO-K1 cells. Tetradecanoylphorbol 13-acetate (TPA) induced irreversible translocation of DCR gamma, but not DGR alpha, from the cytoplasm to the plasma membrane. The (TPA)-induced translocation of DGK gamma was inhibited by the mutation of C1A but not C1B domain of DGH gamma and was not inhibited by staurosporine. Arachidonic acid induced reversible translocation of DGK gamma from the cytoplasm to the plasma membrane, whereas DGK alpha showed irreversible translocation to the plasma membrane and the Golgi network. Purinergic stimulation induced reversible translocation of both DGK gamma and alpha to the plasma membrane. The timing of the ATP-indeed translocation of DGK gamma roughly coincided with that of PKC gamma re-translocation from the membrane to the cytoplasm. Furthermore, re-translocation of PRC gamma was obviously hastened by co-expression with DGK gamma and was blocked by an inhibitor of DGK (R59022). These results indicate that DGK shows subtype-specific translocation depending on extracellular signals and suggest that PRC and DGK are orchestrated temporally and spatially in the signal transduction.