Identification and distribution of endoplasmic reticulum iPLA2

Our laboratory demonstrated that endoplasmic reticulum iPLA(2) (ER-iPLA(2)) activity protects renal cells from oxidant-induced cell death and lipid peroxidation. The goals of this study were to determine the PLA(2) isoform(s) responsible for ER-iPLA(2) activity in different species and tissues. ER-iPLA(2) activity was observed in microsomes from rabbit and rat kidney, heart, and brain as well as in human kidney (Caki-1 and HEK293) and glioblastoma (A172) cell lines. Reverse transcriptase-polymerase chain reaction results demonstrated the presence of iPLA2(T)gamma(group VIB PLA(2)) message in all tissues tested. Immunoblot analysis and PLA2 inhibitor studies with methyl arachidonyl fluorophosphonate and enantiomers of bromoenol lactone demonstrated that the ER-iPLA(2) in rabbit kidney and heart and rat kidney is iPLA(2)gamma. These results demonstrate the expression of ER-iPLA(2)gamma (group VIB) across species and tissues, and suggest that iPLA(2)gamma may play critical roles in oxidant-induced cell injury. (C) 2004 Elsevier Inc. All rights reserved.