Lipoxygenases and their involvement in programmed cell death

Lipoxygenases are a family of enzymes which dioxygenate unsaturated fatty a cids, thus initiating lipoperoxidation of membranes and the synthesis of si gnaling molecules. Consequently, they induce structural and metabolic chang es in the cell in a number of pathophysiological conditions. Recently, a pr o-apoptotic effect of lipoxygenase, and of the hydroperoxides produced ther eof, has been reported in different cells and tissues, leading to cell deat h. Anti-apoptotic effects of lipoxygenases have also been reported; however , this has often been based on the use of enzyme inhibitors, Here we review the characteristics of the lipoxygenase family and its involvement in the initiation of oxidative stress-induced apoptosis. Finally, we discuss the r ole of lipoxygenase activation in apoptosis of animal and plant cells, sugg esting a common signal transduction pathway in cell death conserved through evolution of both kingdoms.