The arachidonic acid-binding protein S100A8/A9 promotes NADPH oxidase activation by interaction with p67phox and Rac-2.
The Ca2+- and arachidonic acid-binding S100A8/A9 protein complex was recently identified by in vitro studies as a novel partner of the phagocyte NADPH oxidase. The present study demonstrated its functional relevance by the impaired oxidase activity in neutrophil-like NB4 cells, after specific blockage of S100A9 expression, and bone marrow polymorphonuclear neutrophils from S100A9-/- mice. The impaired oxidase activation could also be mimicked in a cell-free system by pretreatment of neutrophil cytosol with an S100A9-specific antibody. Further analyses gave insights into the molecular mechanisms by which S100A8/A9 promoted NADPH oxidase activation. In vitro analysis of oxidase activation as well as protein-protein interaction studies revealed that S100A8 is the privileged interaction partner for the NADPH oxidase complex since it bound to p67phox and Rac, whereas S100A9 did interact with neither p67phox nor p47phox. Moreover, S100A8/A9 transferred the cofactor arachidonic acid to NADPH oxidase as shown by the impotence of a mutant S100A8/A9 complex unable to bind arachidonic acid to enhance NADPH oxidase activity. It is concluded that S100A8/A9 plays an important role in phagocyte NADPH oxidase activation.
Kerkhoff
Claus
C
Institute of Experimental Dermatology, University of Münster, Germany. kerkhoc@uni-muenster.de
Nacken
Wolfgang
W
Benedyk
Malgorzata
M
Dagher
Marie Claire
MC
Sopalla
Claudia
C
Doussiere
Jacques
J
D000818:Animals; D016718:Arachidonic Acid / Q000494:pharmacology; D040501:Calgranulin A / Q000235:genetics / Q000502:physiology*; D040502:Calgranulin B / Q000235:genetics / Q000502:physiology*; D002417:Cattle; D045744:Cell Line, Tumor; D002474:Cell-Free System; D004789:Enzyme Activation / Q000187:drug effects; D015870:Gene Expression / Q000187:drug effects; D020868:Gene Silencing; D006801:Humans; D015473:Leukemia, Promyelocytic, Acute; D051379:Mice; D018345:Mice, Knockout; D019255:NADPH Oxidases / Q000378:metabolism*; D009504:Neutrophils / Q000201:enzymology / Q000502:physiology; D016376:Oligonucleotides, Antisense / Q000494:pharmacology; D010750:Phosphoproteins / Q000235:genetics / Q000502:physiology*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000032:analysis; D017382:Reactive Oxygen Species / Q000378:metabolism; D011993:Recombinant Fusion Proteins; D016897:Respiratory Burst; D013481:Superoxides / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D020744:rac GTP-Binding Proteins / Q000502:physiology*; D000097766:RAC2 GTP-Binding Protein
D016718:Arachidonic Acid; D040501:Calgranulin A; D040502:Calgranulin B; D019255:NADPH Oxidases; D016376:Oligonucleotides, Antisense; D010750:Phosphoproteins; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D011993:Recombinant Fusion Proteins; D013481:Superoxides; D013755:Tetradecanoylphorbol Acetate; D020744:rac GTP-Binding Proteins; D000097766:RAC2 GTP-Binding Protein; C079789:neutrophil cytosol factor 67K