p40phox activated phagocyte NADPH oxidase without p47phox in a cell-free system consisting of p67phox, Rac and cytochrome b558 relipidated with phosphatidylinositol 3-phosphate. The activation reached to 70% of that by p47phox. Addition of p47phox slightly increased the activation, but not additively. p40phox improved the efficiency of p67phox in the activation. The C-terminus-truncated p67phox, p40phox(D289A), p40phox(R58A), or p40phox(W207R) showed an impaired activation. A peptide corresponding to the p22phox Pro-rich region suppressed the activation, and far-western blotting revealed its interaction with p40phox SH3 domain. Thus, p40phox can substitute for p47phox in the activation, interacting with p22phox and p67phox through their specific regions.
All Science Journal Classification (ASJC) codes
- Structural Biology
- Molecular Biology
- Cell Biology