Fig. 1. Lipid kinase activity in total cell lysate and detergent insoluble fraction. (A) Total cell lysate (10 µg) and detergent insoluble fraction (DIF) (50 µg) from NIH 3T3 cells were applied to an in vitro lipid kinase assay using PtdIns as substrate. After an incubation of 20 minutes at 37°C, the lipids were extracted, separated on TLC and the PtdIns(4)P spots were quantified (total cell lysates, s.e.m., n=3; DIF, s.e.m., n=4) (^*P<0.01). Adenosine, 200 µM; wortmannin, 1 µM; LY294002, 10 µM. (B) Total cell lysates (10 µg) from NIH 3T3 cells were incubated with increasing amounts of adenosine and applied to an in vitro kinase assay. Results are expressed as the percentage of control activity without adenosine.