出版社：American Society for Biochemistry and Molecular Biology
摘要：The differential activation of different members of the phospholipase A2 (PLA2) superfamily and their regulation are important as one or more of them regulates the production of eicosanoids and others may contribute to the formation of other lipid mediators. We previously reported the existence of two forms of secretory or sPLA2 in mouse keratinocytes, namely type I and type II sPLA2. We show here that mouse keratinocyte sPLA2s were potently activated by protease treatment and inhibited by protease inhibitors. We also observed that G protein effectors induced substantial release of oleic acid (OA) from prelabeled mouse keratinocytes. A G i /G 0 protein activator significantly enhanced the hydrolysis of OA and this increase was not responsive to either pertussis toxin or cholera toxin treatment. Although there was a significant negative correlation between intracellular cAMP levels and OA hydrolysis, experimentally increasing cAMP with forskolin treatment had no effect on sPLA2 activity. Arachidonic acid but not its metabolites was also shown to marginally activate keratinocyte sPLA2 by 1.5-fold. These results lead to the conclusion that mouse keratinocyte sPLA2s can be regulated primarily by proteolytic activation and a G protein pathway. —Li-Stiles, B., and S. M. Fischer. Mechanism(s) of activation of secretory phospholipase A2s in mouse keratinocytes. J. Lipid Res. 1999. 40: 1701–1708.
关键词：arachidonic acid ; G protein ; keratinocytes ; phospholipase A2 ; protease ; secretory phospholipase A2
