FIGURE 1.

The cellular content of DAG can be regulated by PC and PI synthetic pathways. A, enzyme-catalyzed reactions for the synthesis of PC and PI from DAG and the exogenous substrates choline and inositol. The metabolites and the enzymes involved for the experimental strategies used in this work are indicated in rectangular or eliptical boxes, respectively. B, CHO-K1 and CHO-MT58 cells were grown at 33 °C and then shifted to 40 °C for the indicated times. Results are from one experiment representative of three experiments. C, CHO-K1 and NRK cells were incubated for 1 h in HEPES buffer with 200 μm choline and 5 mm inositol (filled bars) or without these substrates in the presence of 5 mm LiCl (open bars). Results are mean ± S.E. (error bars) of three experiments performed in duplicate. PIS, phosphatidylinositol synthase.