Attenuation of p47phox and p67phox membrane translocation as the inhibitory mechanism of S-nitrosothiol on the respiratory burst oxidase in human neutrophils.

The effect of the S-nitrosothiol (RSNO) on the activation of NADPH oxidase in human neutrophils was studied using an in vitro translocation system in which an anionic amphiphil, such as sodium dodecyl sulfate or arachidonate, plays a role as an activator. When membranes pretreated with RSNO and a cytosol fraction from resting neutrophils were combined to reconstitute the NADPH oxidase, both translocation of the cytosolic NADPH oxidase components such as p47phox and p67phox to the plasma membrane fraction and subsequent superoxide generation was inhibited. However, RSNO had no effect on O2- production when added after enzyme activation. A similar inhibition of translocation of recombinant p47phox was observed with RSNO-treated membrane. When the RSNO-treated membrane fraction was exposed to 2-mercaptoethanol the inhibition was reversed. The data suggest that RSNO inhibits translocation of p47phox or p47phox containing cytosolic complex via a direct effect on the membrane component of the NADPH oxidase.