Group V sPLA₂ amplifies ERK-dependent phosphorylation of cPLA₂α. BMMCs from wild-type (left panels) and Pla2g5–null (right panels) mice were incubated for 0 to 60 minutes with 3 μg/mL Pam₃CSK₄. Expression of phosphorylated (p) and total cPLA₂α, ERK-1/2, and p38 was assessed by Western blotting. (A) Representative data from 3 independent experiments are shown. (B-D) Expression of phospho-cPLA₂α (B), phospho-p44 ERK (C), and phospho-p42 ERK was quantified using the Image J software and was expressed as a ratio of the intensity of the respective total protein band (n = 3). Error bars indicate SEM.