title: Interaction between the SH3 domains and C-terminal proline-rich region in NADPH oxidase organizer 1 (Noxo1).
abstract: NADPH oxidase organizer 1 (Noxo1), harboring a PX domain, two SH3 domains, and a proline-rich region (PRR), participates in activation of superoxide-producing Nox-family NADPH oxidases. Here, we show that Noxo1 supports superoxide production in a cell-free system for gp91(phox)/Nox2 activation by arachidonic acid. This lipid enhances an SH3-mediated binding of Noxo1 to p22(phox), a protein complexed with Nox oxidases; the binding is known to be required for Nox activation. We also demonstrate that the bis-SH3 domain directly interacts with the Noxo1 PRR. The interaction appears to prevent the bis-SH3 domain and PRR from binding to their target proteins; disruption of the intramolecular interaction facilitates Noxo1 binding to p22(phox) and also allows the PRR to associate with the Nox activator Noxa1, which association is crucial for Nox activation as well. These findings suggest that Nox activation involves a conformational change leading to disruption of the bis-SH3-PRR interaction in Noxo1.
authors.affiliation: Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Fukuoka 812-8582, Japan.
authors.forename: Asataro
authors.initials: A
authors.lastname: Yamamoto
authors.forename: Keiichiro
authors.initials: K
authors.lastname: Kami
authors.forename: Ryu
authors.initials: R
authors.lastname: Takeya
authors.forename: Hideki
authors.initials: H
authors.lastname: Sumimoto
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport / Q000378:metabolism*; D016718:Arachidonic Acid / Q000008:administration & dosage*; D001665:Binding Sites; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D006801:Humans; D008562:Membrane Glycoproteins / Q000378:metabolism*; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases / Q000378:metabolism*; D009504:Neutrophils / Q000187:drug effects / Q000378:metabolism*; D011392:Proline / Q000378:metabolism*; D011485:Protein Binding; D018909:src Homology Domains / Q000502:physiology
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D008562:Membrane Glycoproteins; C476419:NOXO1 protein, human; D016718:Arachidonic Acid; D011392:Proline; C056558:CYBB protein, human; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases; C086986:CYBA protein, human