title: Roles for proline-rich regions of p47phox and p67phox in the phagocyte NADPH oxidase activation in vitro.
abstract: The cytosolic proteins p47phox and p67phox, each containing two SH3 domains, are required for activation of the superoxide-producing phagocyte NADPH oxidase in a cell-free system with human neutrophil membrane and the small GTPase Rac. Here we focus on roles of proline-rich regions (PRRs) that reside in p47phox and p67phox. Deletion of the p47phox PRR, to which the C-terminal SH3 domain of p67phox binds, results in three-fold decreased activation of the enzyme in the cell-free system with the full-length p67phox, suggesting a modulatory role of the p47phox PRR. The modulation is likely mediated via the C-terminal region of p67phox, since the p47phox mutant protein fully activates the oxidase in combination with the N-terminus of p67phox. Neither deletion of the p67phox PRR nor substitutions for prolines in the region affects the ability to support superoxide production under the cell-free conditions, indicating that the PRR of p67phox has no primary function in the oxidase activation.
authors.affiliation: Department of Biochemistry, Kyushu University School of Medicine, Fukuoka, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Hata
authors.forename: K
authors.initials: K
authors.lastname: Takeshige
authors.forename: H
authors.initials: H
authors.lastname: Sumimoto
mesh_terms: D000595:Amino Acid Sequence; D002474:Cell-Free System; D004252:DNA Mutational Analysis; D004789:Enzyme Activation; D006801:Humans; D008969:Molecular Sequence Data; D016296:Mutagenesis; D019255:NADPH Oxidases / Q000378:metabolism*; D009504:Neutrophils / Q000201:enzymology*; D010586:Phagocytes / Q000201:enzymology*; D010750:Phosphoproteins / Q000378:metabolism*; D011392:Proline / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D017384:Sequence Deletion; D018909:src Homology Domains / Q000235:genetics
chemical_list: D010750:Phosphoproteins; D011993:Recombinant Fusion Proteins; C079789:neutrophil cytosol factor 67K; D011392:Proline; D019255:NADPH Oxidases; C060505:neutrophil cytosolic factor 1