(A) Schematic representation of diacylglycerol metabolism to phosphatidic acid via DGKA. (B) Phosphatidic acid levels are elevated in Tsc2−/− MEFs compared to Tsc2+/+ MEFs. Ritanserin treatment (10uM; 16 hours) decreases PA levels in Tsc2−/− MEFs but not in Tsc2+/+ MEFs. (C-G) DGKA inhibition by ritanserin leads to accumulation of diacylglycerol and phospholipids PI, PC, PS and PE similarly in Tsc2−/− MEFs and in Tsc2+/+ MEFs. Data presented as mean ± SD of the sum of each lipid species from three biological replicates. Statistical significance was assessed using t-test with FDR correction (q<0.05) and *p<0.05, **p<0.01, ***p<0.001, ****p <0.0001.