MAPK p38 alpha activates cPLA2 by phosphorylation of two serine residues.
cPLA2 can be phosphorylated and activated by ERK2 (Lin et al. 1993), and were believed to be responsible for the phosphorylation of cPLA2. However, phosphorylation of cPLA2 occurred in the absence of ERK activation in human platelets stimulated with the thrombin receptor agonist peptide SFLLRN (Kramer et al. 1995), and cPLA2 phosphorylation induced by thrombin or collagen was unaffected by PKC inhibitors that prevent ERK activation (Börsch-Haubold et al. 1995). In addition, a specific inhibitor of ERKs did not block thrombin-induced cPLA2 phosphorylation (Börsch-Haubold et al. 1996).