Diacylglycerol kinases are thought to be involved mainly in the regeneration of phosphatidylinositol (PI) from diacylglycerol in the PI-cycle during cell signal transduction. When expressed in mammalian cells, DGK-epsilon shows specificity for arachidonyl-containing diacylglycerol. DGK-epsilon is expressed predominantly in testis. [provided by RefSeq, Jul 2008].