FIGURE 3.

Direct activation of PLC-ε by K-Ras. K-Ras was purified from detergent-extracted HighFive insect cell membranes as described under “Experimental Procedures,” was reconstituted at various concentrations in phospholipid vesicles containing [³H]PtdIns(4,5)P₂ and was incubated with 10 μm GDP (open circles) or 10 μm GTPγS (closed circles) for 30 min at 30 °C. The assay was initiated by the addition of purified PLC-ε-EF-RA2 (2 ng) and incubations were continued for 8 min at 30 °C. The results are the mean ± S.E. of a representative experiment performed six times.