Inhibition of basal PLD1 activity correlates with reduced PA formation and morphologic changes. (A) Basal PLD activity; (B) basal PA formation. The indicated cell lines were labeled with [¹⁴C]lysoPC for 90 minutes and then cultured for 24 hours. For the transphosphatidylation, cells were incubated with 0.25% 1-butanol for another 1 hour, and the labeled PBut (A) or PA (B) was then separated on thin-layer chromatography (TLC). Data represent the mean ± SD from at least 5 independent experiments. Statistically significant change compared with the 2 control cells is indicated as follows: ^*P < .05, ^**P < .005.