p40phox as an alternative organizer to p47phox in Nox2 activation: a new mechanism involving an interaction with p22phox.
p40(phox) activated phagocyte NADPH oxidase without p47(phox) in a cell-free system consisting of p67(phox), Rac and cytochrome b(558) relipidated with phosphatidylinositol 3-phosphate. The activation reached to 70% of that by p47(phox). Addition of p47(phox) slightly increased the activation, but not additively. p40(phox) improved the efficiency of p67(phox) in the activation. The C-terminus-truncated p67(phox), p40(phox)(D289A), p40(phox)(R58A), or p40(phox)(W207R) showed an impaired activation. A peptide corresponding to the p22(phox) Pro-rich region suppressed the activation, and far-western blotting revealed its interaction with p40(phox) SH3 domain. Thus, p40(phox) can substitute for p47(phox) in the activation, interacting with p22(phox) and p67(phox) through their specific regions.
Tamura
Minoru
M
Department of Applied Chemistry, Graduate School of Science and Engineering, Ehime University, Matsuyama, Ehime 790-8577, Japan. tamura@eng.ehime-u.ac.jp
Shiozaki
Iichiro
I
Ono
Shohei
S
Miyano
Kei
K
Kunihiro
Sachio
S
Sasaki
Takayuki
T
D000595:Amino Acid Sequence; D000818:Animals; D026481:Blotting, Far-Western; D002417:Cattle; D002474:Cell-Free System; D004789:Enzyme Activation / Q000187:drug effects; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D019255:NADPH Oxidases / Q000235:genetics / Q000378:metabolism*; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D017386:Sequence Homology, Amino Acid; D012967:Sodium Dodecyl Sulfate / Q000494:pharmacology; D018909:src Homology Domains