Diacylglycerol (DAG) kinases (DGKs) phosphorylate DAG to give phosphatidic acid (PA), reducing signaling through DAG and increasing signaling through PA. R-59-022 is an inhibitor of DGK (IC50 = 2.8 μM). This results in increased DAG-dependent PKC activity and potentiates aggregation of thrombin-stimulated platelets. R-59-022 also blocks vascular contraction induced by the thromboxane analog U-46619 . At 10 μM, R-59-022 induces apoptosis in glioblastoma cells without being toxic to non-cancerous cells. It inhibits DGK-θ in vitro at concentrations below 1 μM and blocks DGK-θ activity in vivo. R-59-022 also inhibits A. thaliana DGK2 (IC50 = 50 μM) and suppresses root growth but does not affect DGK7 at 50 μM.
