THE ROLE OF DIACYLGLYCEROL KINASE ACTIVATION AND PHOSPHATIDATE ACCUMULATION IN INTERLEUKIN-2-DEPENDENT LYMPHOCYTE-PROLIFERATION

The biological effects of interleukin-2 (IL-2) were examined in T lymp hocytes. IL-2 binding induced the rapid activation of diacylglycerol k inase in both cytosolic and membrane subfractions. This enzyme utilize d diacylglycerol from multiple endogenous and exogenous sources for th e synthesis of phosphatidic acid. Phosphatidic acid was, in turn, show n to stimulate the accumulation of c-myc mRNA and augment cellular pro liferation when added to IL-2-dependent cell lines. These results link previous observations of IL-2 and glycosylphosphatidylinositol-depend ent diacylglycerol production to phosphatidic acid accumulation, and s uggest that diacylglycerol kinase activation is part of an intricate I L-2 signaling cascade that utilizes phosphatidic acid as an effector m olecule.