Group IVC cytosolic phospholipase A2 γ is farnesylated and palmitoylated in mammalian cells

Cytosolic phospholipase A(2)gamma( cPLA(2)gamma) is a member of the group IV family of intracellular phospholipase A 2 enzymes, but unlike the well- studied cPLA(2)alpha, it is constitutively bound to membrane and is calcium independent. cPLA(2)gamma contains a C- terminal CaaX sequence and is radiolabeled by mevalonic acid when expressed in cPLA(2)alpha- deficient immortalized lung fibroblasts ( IMLF (-/-)). The radiolabel associated with cPLA(2)gamma was identified as the farnesyl group. The protein farnesyltransferase inhibitor BMS- 214662 prevented the incorporation of [ 3 H] mevalonic acid into cPLA(2)gamma and partially suppressed serum- stimulated arachidonic acid release from IMLF-/- and undifferentiated human skeletal muscle ( SkMc) cells overexpressing cPLA(2) gamma, but not from cells overexpressing cPLA(2)alpha. However, BMS-214662 did not alter the amount of cPLA(2)gamma associated with membrane. These results were consistent in COS cells expressing the C538S cPLA(2)gamma prenylation mutant. cPLA(2)gamma also contains a classic myristoylation site and several potential palmitoylation sites and was found to be acylated with oleic and palmitic acids but not myristoylated. Immunofluorescence microscopy revealed that cPLA(2)gamma is associated with mitochondria in IMLF (-/-), SkMc cells, and COS cells.