Localization of Rat Liver Group IIA Phospholipase A(2) in Secretory Pathways: Green Fluorescent Protein Approach

Rat liver group IIA phospholipase A(2) (PLA(2), Enzyme Commission Number [E.C.] 3.1.1.4) was initially isolated from mitochondria. Since then it has been thought that it resides in mitochondria and that mitochondria are its main subcellular target. We cloned the cDNA sequence of rat group IIA PLA(2) and fused its presequence (signal peptide) to enhanced green fluorescent protein (EGFP). In baby hamster kidney (BHK) cells transiently and stably expressing the fusion protein, the fluorescence does not localize in mitochondria, but rather in the secretory pathway. These results suggest that the plasma membrane, and not mitochondria, is the primary target of rat group IIA PLA(2).