title: Unique targeting of cytosolic phospholipase A2 to plasma membranes mediated by the NADPH oxidase in phagocytes.
abstract: Cytosolic phospholipase A2 (cPLA2)-generated arachidonic acid (AA) has been shown to be an essential requirement for the activation of NADPH oxidase, in addition to its being the major enzyme involved in the formation of eicosanoid at the nuclear membranes. The mechanism by which cPLA2 regulates NADPH oxidase activity is not known, particularly since the NADPH oxidase complex is localized in the plasma membranes of stimulated cells. The present study is the first to demonstrate that upon stimulation cPLA2 is transiently recruited to the plasma membranes by a functional NADPH oxidase in neutrophils and in granulocyte-like PLB-985 cells. Coimmunoprecipitation experiments and double labeling immunofluorescence analysis demonstrated the unique colocalization of cPLA2 and the NADPH oxidase in plasma membranes of stimulated cells, in correlation with the kinetic burst of superoxide production. A specific affinity in vitro binding was detected between GST-p47phox or GST-p67phox and cPLA2 in lysates of stimulated cells. The association between these two enzymes provides the molecular basis for AA released by cPLA2 to activate the assembled NADPH oxidase. The ability of cPLA2 to regulate two different functions in the same cells (superoxide generation and eicosanoid production) is achieved by a novel dual subcellular localization of cPLA2 to different targets.
authors.affiliation: Infectious Diseases Laboratory, Department of Clinical Biochemistry, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel.
authors.forename: Zeev
authors.initials: Z
authors.lastname: Shmelzer
authors.forename: Nurit
authors.initials: N
authors.lastname: Haddad
authors.forename: Ester
authors.initials: E
authors.lastname: Admon
authors.forename: Itai
authors.initials: I
authors.lastname: Pessach
authors.forename: Thomas L
authors.initials: TL
authors.lastname: Leto
authors.forename: Zahit
authors.initials: Z
authors.lastname: Eitan-Hazan
authors.forename: Michal
authors.initials: M
authors.lastname: Hershfinkel
authors.forename: Rachel
authors.initials: R
authors.lastname: Levy
mesh_terms: D002462:Cell Membrane / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism*; D006801:Humans; D019255:NADPH Oxidases / Q000378:metabolism*; D010586:Phagocytes / Q000378:metabolism*; D010741:Phospholipases A / Q000378:metabolism*; D054467:Phospholipases A2; D011233:Precipitin Tests
chemical_list: D019255:NADPH Oxidases; D010741:Phospholipases A; D054467:Phospholipases A2