The requirement of cytosolic phospholipase A2 for the PMA activation of proton efflux through the N-terminal 230-amino-acid fragment of gp91phox

Tosti J. Mankelow, Etai Pessach, Rachel Levy, Lydia M. Henderson

    Research output: Contribution to journalArticlepeer-review

    14 Scopus citations

    Abstract

    The absolute requirement for the 85 kDa cytosolic phospholipase A 2 (cPLA2) in the PMA stimulation of proton efflux through the NADPH-oxidase-associated proton channel, has previously been demonstrated using a PLB-985 cell line deficient in cPLA2 (PLB-D). The flux of protons in Chinese-Hamster ovary (CHO) cells that express the N-terminal 230-amino-acid (NT) fragment of gp91phox is activated by arachidonic acid (AA) added externally. To investigate the physiological role of cPLA 2, and the intracellular AA that it releases, in the activation of proton flux through the NT fragment of gp91phox, this fragment was stably expressed in PLB-985 cells (PLB-985 NT) and in PLB-D cells (PLB-D NT). The expression of the NT fragment of gp91phox by itself in PLB-985 did not initiate differentiation and did not alter their ability to undergo differentiation after the addition of DMSO. Addition of PMA induced a proton efflux from undifferentiated PLB-985 NT cells expressing the NT fragment of gp91phox, which was inhibited by zinc. In contrast, PMA failed to activate proton efflux in undifferentiated PLB-D NT cells, lacking the expression of cPLA2; however, addition of AA restored the efflux of protons in these cells. These results establish an essential and specific physiological requirement of cPLA2-generated AA in the activation of proton flux through the NT fragment of gp91phox.

    Original languageEnglish
    Pages (from-to)315-319
    Number of pages5
    JournalBiochemical Journal
    Volume374
    Issue number2
    DOIs
    StatePublished - 1 Sep 2003

    Keywords

    • Arachidonic acid
    • NADPH oxidase
    • Phospholipase A
    • Proton channel
    • gp91

    ASJC Scopus subject areas

    • Biochemistry
    • Molecular Biology
    • Cell Biology

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