Taiwan cobra phospholipase A2 (PLA2) treatment promoted proADAM17 processing into mature ADAM17 in human neuroblastoma SK-N-SH cells. The abolishment of catalytic activity caused a drastic drop in the PLA2 ability to induce ADAM17 maturation, and lysophosphatidylcholine treatment mimicked the effect of PLA2. ADAM17 activity measurement, ADAM17 cell surface levels, TNFR2 ectodomain shedding, and ADAM17 mRNA transcription supported that posttranscriptional up-regulation of ADAM17 occurred in PLA2-treated SK-N-SH cells. PLA2 treatment induced p38 MAPK activation and ERK inactivation. p38 MAPK activation suppression by SB202190 (p38 MAPK inhibitor) abolished posttranscriptional up-regulation of ADAM17 in PLA2-treated cells, while treatment with U0126 (MEK1 and MEK2 inhibitor) increased ADAM17 maturation in SK-N-SH cells. Constitutively active MEK1 expression abrogated PLA2-induced ADAM17 maturation. Taken together, our data indicate that PLA2-evoked p38 MAPK activation and ERK inactivation are involved in ADAM17 posttranscriptional up-regulation, and suggest that the action of PLA2 is catalytic activity-dependent. J. Cell. Biochem. 111: 148–157, 2010. © 2010 Wiley-Liss, Inc.