TY - JOUR
T1 - Anionic amphiphile-independent activation of the phagocyte NADPH oxidase in a cell-free system by p47(phox) and p67(phox), both in C terminally truncated forms. Implication for regulatory Src homology 3 domain-mediated interactions
AU - Hata, Kenichiro
AU - Ito, Takashi
AU - Takeshige, Koichiro
AU - Sumimoto, Hideki
N1 - Copyright:
Copyright 2007 Elsevier B.V., All rights reserved.
PY - 1998/2/13
Y1 - 1998/2/13
N2 - Anionic amphiphiles, such as arachidonate, activate the superoxide- producing phagocyte NADPH oxidase in a cell-free system with human neutrophil membrane, which contains cytochrome b558 comprising gp91(phox) and p22(phox), and three cytosolic proteins: p47(phox) and p67(phox), each harboring two SH3 domains, and the small GTPase Rac. Here we show that, even without the amphiphiles, the oxidase is activated in vitro by a C terminally truncated p47(phox), retaining the N-terminal and the two SH3 domains, and the N terminus of p67(phox). When either truncated p47(phox) or p67(phox) is replaced by the respective full-length one, the activation absolutely requires the amphiphiles. The results indicate that both p47(phox) and p67(phox) are the primary targets of the amphiphiles, and that their C- terminal regions play negative regulatory roles. We also find that the truncated p47(phox), but not the full-length one, can bind to p22(phox), a binding required for the oxidase activation. The N-terminal SH3 domain of p47(phox) is responsible for the binding not only to p22(phox), but also to the p47(phox) C terminus. Thus the SH3 domain is accessible in the active p47(phox), but is normally masked in the full-length one probably via intramolecularly interacting with the C terminus. The present findings support our previous proposal of regulatory SH3 domain-mediated interactions.
AB - Anionic amphiphiles, such as arachidonate, activate the superoxide- producing phagocyte NADPH oxidase in a cell-free system with human neutrophil membrane, which contains cytochrome b558 comprising gp91(phox) and p22(phox), and three cytosolic proteins: p47(phox) and p67(phox), each harboring two SH3 domains, and the small GTPase Rac. Here we show that, even without the amphiphiles, the oxidase is activated in vitro by a C terminally truncated p47(phox), retaining the N-terminal and the two SH3 domains, and the N terminus of p67(phox). When either truncated p47(phox) or p67(phox) is replaced by the respective full-length one, the activation absolutely requires the amphiphiles. The results indicate that both p47(phox) and p67(phox) are the primary targets of the amphiphiles, and that their C- terminal regions play negative regulatory roles. We also find that the truncated p47(phox), but not the full-length one, can bind to p22(phox), a binding required for the oxidase activation. The N-terminal SH3 domain of p47(phox) is responsible for the binding not only to p22(phox), but also to the p47(phox) C terminus. Thus the SH3 domain is accessible in the active p47(phox), but is normally masked in the full-length one probably via intramolecularly interacting with the C terminus. The present findings support our previous proposal of regulatory SH3 domain-mediated interactions.
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U2 - 10.1074/jbc.273.7.4232
DO - 10.1074/jbc.273.7.4232
M3 - Article
C2 - 9461621
AN - SCOPUS:0032512773
VL - 273
SP - 4232
EP - 4236
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 7
ER -