Diacylglycerol kinases are important regulators of lipid signaling and, consequently, important regulators of many diglyceride-dependent and PA-dependent proteins. Research over the last twenty years has clearly demonstrated that individual DGK isoforms can be connected with disparate cellular processes, indicating the presence of a sophisticated regulatory network for diglyceride and phosphatidic acid signaling through the regulation of individual DGK isoforms. This review presents the progress on the characterization of a primarily neuronal isoform DGK-theta, and examines current data on the primary structure, regulation and potential cellular functions of this enzyme.