The arachidonate-activatable, NADPH oxidase-associated H+ channel is contained within the multi-membrane-spanning N-terminal region of gp91-phox

Abstract

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