THE ARACHIDONATE-ACTIVATABLE, NADPH OXIDASE-ASSOCIATED H-MEMBRANE-SPANNING N-TERMINAL REGION OF GP91-PHOX( CHANNEL IS CONTAINED WITHIN THE MULTI)

The generation of superoxide by the NADPH oxidase of neutrophils is ac companied by the efflux of H+ ions through a H+ channel. gp91-phox, a protein component of the oxidase, has been shown previously to functio n as a H+ channel [Henderson, Banting and Chappell (1995) J. Biol. Che m. 270, 5909-5916]. We have constructed a CHO cell line (CHO-N) that e xpresses an N-terminal fragment of gp91-phox containing the predicted multiple transmembrane domains of the protein. These cells exhibit Hfluxes in response to an imposed proton motive force and in the presen ce of arachidonate (to open the channel). The H+ fluxes were indisting uishable from those observed in cells expressing full-length gp91-phox . Therefore the N-terminal 230 amino acids of gp91-phox contain all th at is required to function as the NADPH oxidase-associated H+ channel.