Cytosolic phospholipase A2γ (cPLA2γ) is farnesylated when expressed in immortalized mouse lung fibroblasts lacking group IVA cPLA2α (IMLF−/−). A: cPLA2γ was immunoprecipitated from [3H]mevalonic acid-labeled IMLF−/−, separated by SDS-PAGE, and subjected to fluorography. B: Reverse-phase HPLC analysis of the radiolabeled hydrocarbon material released from immunoprecipitated cPLA2γ that was treated with Raney-nickel. Fractions were collected every 2 min and submitted to scintillation counting to provide dpm of radioactive material, which is plotted. The arrows indicate the elution positions of the 15 carbon all-trans-2,6,10-tri-methyl-2,6,10-dodecatriene (derived from the farnesyl group) and the 20 carbon all-trans-2,6,10,14-tetramethyl-2,6,10,14-hexadecateratraene (derived from the geranylgeranyl group). These retention times are derived by monitoring the absorbance at 210 nm (not shown) to detect the authentic hydrocarbons derived from Raney-nickel cleavage of the N-acetyl-cysteine(S-prenyl) standards that were added to the reaction mixture (see Methods).