ERK and p38 MAPK‐regulated peroxiredoxin 6 localization to lamellar bodies in MLE 12 cells

Abstract

Peroxiredoxin 6 (Prdx6), a protein with both GSH peroxidase and phospholipase A2 (aiPLA2) activities, participates in lung surfactant phospholipid turnover and protects lung epithelium against oxidative stress. Prdx6 has been localized by immunocytochemistry and sub‐cellular fractionation to cytosol and acidic compartments (lamellar bodies and lysosomes) in lung alveolar epithelium. We postulate that Prdx6 subcellular localization determines the balance between the 2 activities. Using a GFP‐Prdx6 fusion protein, we show that ERK and p38 MAPK regulate Prdx6 localization to organellar structures compatible with lamellar bodies in the MLE12 mouse type II alveolar epithelial cell line. Treatment of GFP‐Prdx6 transfected MLE12 cells with PD98059 and SB202190, inhibitors of ERK and p38 MAPK, respectively, abolished Prdx6 organellar targeting; a JNK kinase inhibitor had no effect. Using mutagenesis, we show that Prdx6 organellar localization is determined by the 31–40 amino acid region which contains a phospholipid binding sequence GDSWG. Serine to alanine (S32A) mutation within this sequence abolished targeting and decreased protein binding to phospholipids as determined by FRET analysis. These studies suggest that Prdx6 targeting to acidic organelles and its consequent PLA2 activity may be determined by MAPK‐regulated lipid binding to a specific Prdx6 amino acid sequence. [HL019737]