Membrane-dependent activities of human 15-lox-2 and its murine counterpart implications for murine models of atherosclerosis
© 2016 by The American Society for Biochemistry and Molecular Biology, Inc. The enzyme encoded by the ALOX15B gene has been linked to the development of atherosclerotic plaques in humans and in a mouse model of hypercholesterolemia. In vitro, these enzymes, which share 78% sequence identity, generate distinct products from their substrate arachidonic acid: the human enzyme, a 15-S-hydroperoxy product; and the murine enzyme, an 8-S-product. We probed the activities of these enzymes with nanodiscs as membrane mimics to determine whether they can access substrate esterified in a bilayer and characterized their activities at the membrane interface. We observed that both enzymes transform phospholipid-esterified arachidonic acid to a 15-S-product. Moreover, when expressed in transfected HEK cells, both enzymes result in significant increases in the amounts of 15-hydroxyderivatives of eicosanoids detected. In addition, we show that 15-LOX-2 is distributed at the plasma membrane when the HEK293 cells are stimulated by the addition Ca 2+ ionophore and that cellular localization is dependent upon the presence of a putative membrane insertion loop. We also report that sequence differences between the human and mouse enzymes in this loop appear to confer distinct mechanisms of enzyme-membrane interaction for the homologues.
Publication Source (Journal or Book title)
Journal of Biological Chemistry
Bender, G., Schexnaydre, E., Murphy, R., Uhlson, C., & Newcomer, M. (2016). Membrane-dependent activities of human 15-lox-2 and its murine counterpart implications for murine models of atherosclerosis. Journal of Biological Chemistry, 291 (37), 19413-19424. https://doi.org/10.1074/jbc.M116.741454