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Herb M. NADPH Oxidase 3: Beyond the Inner Ear. Antioxidants (Basel) 2024; 13:219. [PMID: 38397817 PMCID: PMC10886416 DOI: 10.3390/antiox13020219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2024] [Revised: 02/02/2024] [Accepted: 02/06/2024] [Indexed: 02/25/2024] Open
Abstract
Reactive oxygen species (ROS) were formerly known as mere byproducts of metabolism with damaging effects on cellular structures. The discovery and description of NADPH oxidases (Nox) as a whole enzyme family that only produce this harmful group of molecules was surprising. After intensive research, seven Nox isoforms were discovered, described and extensively studied. Among them, the NADPH oxidase 3 is the perhaps most underrated Nox isoform, since it was firstly discovered in the inner ear. This stigma of Nox3 as "being only expressed in the inner ear" was also used by me several times. Therefore, the question arose whether this sentence is still valid or even usable. To this end, this review solely focuses on Nox3 and summarizes its discovery, the structural components, the activating and regulating factors, the expression in cells, tissues and organs, as well as the beneficial and detrimental effects of Nox3-mediated ROS production on body functions. Furthermore, the involvement of Nox3-derived ROS in diseases progression and, accordingly, as a potential target for disease treatment, will be discussed.
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Affiliation(s)
- Marc Herb
- Institute for Medical Microbiology, Immunology and Hygiene, Faculty of Medicine, University Hospital Cologne, University of Cologne, 50935 Cologne, Germany;
- German Centre for Infection Research, Partner Site Bonn-Cologne, 50931 Cologne, Germany
- Cologne Cluster of Excellence on Cellular Stress Responses in Aging-Associated Diseases (CECAD), 50931 Cologne, Germany
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2
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Bakri FG, Mollin M, Beaumel S, Vigne B, Roux-Buisson N, Al-Wahadneh AM, Alzyoud RM, Hayajneh WA, Daoud AK, Shukair MEA, Karadshe MF, Sarhan MM, Al-Ramahi JAW, Fauré J, Rendu J, Stasia MJ. Second Report of Chronic Granulomatous Disease in Jordan: Clinical and Genetic Description of 31 Patients From 21 Different Families, Including Families From Lybia and Iraq. Front Immunol 2021; 12:639226. [PMID: 33746979 PMCID: PMC7973097 DOI: 10.3389/fimmu.2021.639226] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 02/08/2021] [Indexed: 11/13/2022] Open
Abstract
Chronic granulomatous Disease (CGD) is a rare innate immunodeficiency disorder caused by mutations in one of the six genes (CYBA, CYBB, NCF1, NCF2, NCF4, and CYBC1/EROS) encoding the superoxide-producing nicotinamide adenine dinucleotide phosphate (NADPH)—oxidase complex in phagocytes. In the Western population, the most prevalent form of CGD (about two-thirds of all cases) is the X-linked form (X-CGD) caused by mutations in CYBB. The autosomal recessive forms (AR-CGD), due to mutations in the other genes, collectively account for the remaining one-third of CGD cases. We investigated the clinical and molecular features of 22 Jordanian, 7 Libyan, and 2 Iraqi CGD patients from 21 different families. In addition, 11 sibling patients from these families were suspected to have been died from CGD as suggested by their familial and clinical history. All patients except 9 were children of consanguineous parents. Most of the patients suffered from AR-CGD, with mutations in CYBA, NCF1, and NCF2, encoding p22phox, p47phox, and p67phox proteins, respectively. AR-CGD was the most frequent form, in Jordan probably because consanguineous marriages are common in this country. Only one patient from non-consanguineous parents suffered from an X910 CGD subtype (0 indicates no protein expression). AR670 CGD and AR220 CGD appeared to be the most frequently found sub-types but also the most severe clinical forms compared to AR470 CGD. As a geographical clustering of 11 patients from eight Jordanian families exhibited the c.1171_1175delAAGCT mutation in NCF2, segregation analysis with nine polymorphic markers overlapping NCF2 indicates that a common ancestor has arisen ~1,075 years ago.
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Affiliation(s)
- Faris Ghalib Bakri
- Division of Infectious Diseases, Department of Medicine, Jordan University Hospital, Amman, Jordan.,Infectious Diseases and Vaccine Center, University of Jordan, Amman, Jordan
| | - Michelle Mollin
- Centre Hospitalier Universitaire Grenoble Alpes, Pôle de Biologie, Chronic Granulomatous Disease Diagnosis and Research Centre (CDiReC), Grenoble, France
| | - Sylvain Beaumel
- Centre Hospitalier Universitaire Grenoble Alpes, Pôle de Biologie, Chronic Granulomatous Disease Diagnosis and Research Centre (CDiReC), Grenoble, France
| | - Bénédicte Vigne
- Centre Hospitalier Universitaire Grenoble Alpes, Pôle de Biologie, Chronic Granulomatous Disease Diagnosis and Research Centre (CDiReC), Grenoble, France
| | - Nathalie Roux-Buisson
- Centre Hospitalier Universitaire Grenoble Alpes, Pôle de Biologie, Laboratoire de Biochimie et Génétique Moléculaire, La Tronche, France.,Université Grenoble Alpes, Inserm U1216, Grenoble Institut Neurosciences, Grenoble, France
| | | | - Raed Mohammed Alzyoud
- Division of Immunology, Department of Pediatrics, Queen Rani Children's Hospital, Amman, Jordan
| | - Wail Ahmad Hayajneh
- Division of Infectious Diseases, Department of Pediatrics, Jordan University of Science & Technology, Irbid, Jordan
| | - Ammar Khaled Daoud
- Division of Immunology, Jordan University of Science & Technology, Irbid, Jordan
| | | | | | | | | | - Julien Fauré
- Centre Hospitalier Universitaire Grenoble Alpes, Pôle de Biologie, Laboratoire de Biochimie et Génétique Moléculaire, La Tronche, France.,Université Grenoble Alpes, Inserm U1216, Grenoble Institut Neurosciences, Grenoble, France
| | - John Rendu
- Centre Hospitalier Universitaire Grenoble Alpes, Pôle de Biologie, Laboratoire de Biochimie et Génétique Moléculaire, La Tronche, France.,Université Grenoble Alpes, Inserm U1216, Grenoble Institut Neurosciences, Grenoble, France
| | - Marie Jose Stasia
- Centre Hospitalier Universitaire Grenoble Alpes, Pôle de Biologie, Chronic Granulomatous Disease Diagnosis and Research Centre (CDiReC), Grenoble, France.,Université Grenoble Alpes, Commissariat à l'Energie Atomique (CEA), Centre National de la Recherche Scientifique (CNRS), Institut de Biologie Structurale (IBS), Grenoble, France
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3
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Chanin RB, Winter MG, Spiga L, Hughes ER, Zhu W, Taylor SJ, Arenales A, Gillis CC, Büttner L, Jimenez AG, Smoot MP, Santos RL, Winter SE. Epithelial-Derived Reactive Oxygen Species Enable AppBCX-Mediated Aerobic Respiration of Escherichia coli during Intestinal Inflammation. Cell Host Microbe 2020; 28:780-788.e5. [PMID: 33053375 DOI: 10.1016/j.chom.2020.09.005] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 07/06/2020] [Accepted: 09/03/2020] [Indexed: 12/19/2022]
Abstract
The intestinal epithelium separates host tissue and gut-associated microbial communities. During inflammation, the host releases reactive oxygen and nitrogen species as an antimicrobial response. The impact of these radicals on gut microbes is incompletely understood. We discovered that the cryptic appBCX genes, predicted to encode a cytochrome bd-II oxidase, conferred a fitness advantage for E. coli in chemical and genetic models of non-infectious colitis. This fitness advantage was absent in mice that lacked epithelial NADPH oxidase 1 (NOX1) activity. In laboratory growth experiments, supplementation with exogenous hydrogen peroxide enhanced E. coli growth through AppBCX-mediated respiration in a catalase-dependent manner. We conclude that epithelial-derived reactive oxygen species are degraded in the gut lumen, which gives rise to molecular oxygen that supports the aerobic respiration of E. coli. This work illustrates how epithelial host responses intersect with gut microbial metabolism in the context of gut inflammation.
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Affiliation(s)
- Rachael B Chanin
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Maria G Winter
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Luisella Spiga
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Elizabeth R Hughes
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Wenhan Zhu
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Savannah J Taylor
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Alexandre Arenales
- Departamento de Clínica e Cirurgia Veterinárias, Escola de Veterinária, Universidade Federal de Minas Gerais, Belo Horizonte, MG 31270, Brazil
| | - Caroline C Gillis
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Lisa Büttner
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Angel G Jimenez
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Madeline P Smoot
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Renato L Santos
- Departamento de Clínica e Cirurgia Veterinárias, Escola de Veterinária, Universidade Federal de Minas Gerais, Belo Horizonte, MG 31270, Brazil
| | - Sebastian E Winter
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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4
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Bechor E, Zahavi A, Amichay M, Fradin T, Federman A, Berdichevsky Y, Pick E. p67phoxbinds to a newly identified site in Nox2 following the disengagement of an intramolecular bond—Canaan sighted? J Leukoc Biol 2020; 107:509-528. [DOI: 10.1002/jlb.4a1219-607r] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 12/16/2019] [Accepted: 01/07/2020] [Indexed: 11/10/2022] Open
Affiliation(s)
- Edna Bechor
- The Julius Friedrich Cohnheim Laboratory of Phagocyte ResearchDepartment of Clinical Microbiology and ImmunologySackler School of MedicineTel Aviv University Tel Aviv Israel
| | - Anat Zahavi
- The Julius Friedrich Cohnheim Laboratory of Phagocyte ResearchDepartment of Clinical Microbiology and ImmunologySackler School of MedicineTel Aviv University Tel Aviv Israel
| | - Maya Amichay
- The Julius Friedrich Cohnheim Laboratory of Phagocyte ResearchDepartment of Clinical Microbiology and ImmunologySackler School of MedicineTel Aviv University Tel Aviv Israel
| | - Tanya Fradin
- The Julius Friedrich Cohnheim Laboratory of Phagocyte ResearchDepartment of Clinical Microbiology and ImmunologySackler School of MedicineTel Aviv University Tel Aviv Israel
| | - Aya Federman
- The Julius Friedrich Cohnheim Laboratory of Phagocyte ResearchDepartment of Clinical Microbiology and ImmunologySackler School of MedicineTel Aviv University Tel Aviv Israel
| | - Yevgeny Berdichevsky
- The Julius Friedrich Cohnheim Laboratory of Phagocyte ResearchDepartment of Clinical Microbiology and ImmunologySackler School of MedicineTel Aviv University Tel Aviv Israel
| | - Edgar Pick
- The Julius Friedrich Cohnheim Laboratory of Phagocyte ResearchDepartment of Clinical Microbiology and ImmunologySackler School of MedicineTel Aviv University Tel Aviv Israel
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5
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Abstract
A growing appreciation of NADPH oxidases (NOXs) as mediators of fundamental physiological processes and as important players in myriad diseases has led many laboratories on a search for specific inhibitors to help dissect the role in a given pathway or pathological condition. To date, there are only a few available inhibitors with a demonstrated specificity for a given isozyme. Among those, peptidic inhibitors have the advantage of being designed to target very specific protein-protein interactions that are essential for NOX activity. Herein, we provide the techniques to deliver these inhibitors both in cell culture as well as in vivo.
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6
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Parascandolo A, Laukkanen MO. Carcinogenesis and Reactive Oxygen Species Signaling: Interaction of the NADPH Oxidase NOX1-5 and Superoxide Dismutase 1-3 Signal Transduction Pathways. Antioxid Redox Signal 2019; 30:443-486. [PMID: 29478325 PMCID: PMC6393772 DOI: 10.1089/ars.2017.7268] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 02/21/2018] [Accepted: 02/22/2018] [Indexed: 02/06/2023]
Abstract
SIGNIFICANCE Reduction/oxidation (redox) balance could be defined as an even distribution of reduction and oxidation complementary processes and their reaction end products. There is a consensus that aberrant levels of reactive oxygen species (ROS), commonly observed in cancer, stimulate primary cell immortalization and progression of carcinogenesis. However, the mechanism how different ROS regulate redox balance is not completely understood. Recent Advances: In the current review, we have summarized the main signaling cascades inducing NADPH oxidase NOX1-5 and superoxide dismutase (SOD) 1-3 expression and their connection to cell proliferation, immortalization, transformation, and CD34+ cell differentiation in thyroid, colon, lung, breast, and hematological cancers. CRITICAL ISSUES Interestingly, many of the signaling pathways activating redox enzymes or mediating the effect of ROS are common, such as pathways initiated from G protein-coupled receptors and tyrosine kinase receptors involving protein kinase A, phospholipase C, calcium, and small GTPase signaling molecules. FUTURE DIRECTIONS The clarification of interaction of signal transduction pathways could explain how cells regulate redox balance and may even provide means to inhibit the accumulation of harmful levels of ROS in human pathologies.
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7
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Sumimoto H, Minakami R, Miyano K. Soluble Regulatory Proteins for Activation of NOX Family NADPH Oxidases. Methods Mol Biol 2019; 1982:121-137. [PMID: 31172470 DOI: 10.1007/978-1-4939-9424-3_8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
NOX family NADPH oxidases deliberately produce reactive oxygen species and thus contribute to a variety of biological functions. Of seven members in the human family, the three oxidases NOX2, NOX1, and NOX3 form a heterodimer with p22phox and are regulated by soluble regulatory proteins: p47phox, its related organizer NOXO1; p67phox, its related activator NOXA1; p40phox; and the small GTPase Rac. Activation of the phagocyte oxidase NOX2 requires p47phox, p67phox, and GTP-bound Rac. In addition to these regulators, p40phox plays a crucial role when NOX2 is activated during phagocytosis. On the other hand, NOX1 activation prefers NOXO1 and NOXA1, although Rac is also involved. NOX3 constitutively produces superoxide, which is enhanced by regulatory proteins such as p47phox, NOXO1, and p67phox. Here we describe mechanisms for NOX activation with special attention to the soluble regulatory proteins.
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Affiliation(s)
- Hideki Sumimoto
- Department of Biochemistry, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan.
| | - Reiko Minakami
- Department of Biochemistry, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan
| | - Kei Miyano
- Department of Biochemistry, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan
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8
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Pick E. Using Synthetic Peptides for Exploring Protein-Protein Interactions in the Assembly of the NADPH Oxidase Complex. Methods Mol Biol 2019; 1982:377-415. [PMID: 31172485 DOI: 10.1007/978-1-4939-9424-3_23] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The NADPH oxidase complex, responsible for reactive oxygen species (ROS) generation by phagocytes, consists of a membrane-associated flavocytochrome b 558 (a heterodimer of NOX2 and p22phox) and the cytosolic components p47phox, p67phox, Rac(1 or 2), and p40phox. NOX2 carries all redox stations through which electrons flow from NADPH to molecular oxygen, to generate the primary ROS, superoxide. For the electron flow to start, a conformational change in NOX2 is required. The dominant hypothesis is that this change is the result of the interaction of NOX2 with one or more of the cytosolic components (NADPH oxidase assembly). At the most basic level, assembly is the sum of several protein-protein interactions among oxidase components. This chapter describes a reductionist approach to the identification of regions in oxidase components involved in assembly. This approach consists of "transforming" one component in an array of overlapping synthetic peptides and assessing binding to the peptides of another component, represented by a recombinant protein. The peptides are tagged with biotin, at the N- or C-terminus, and immobilized on streptavidin-coated 96-well plates. The protein partners are expressed with a 6His tag and added to the plates in the fluid phase. Binding of the protein to the peptides is quantified by a kinetic ELISA , using a peroxidase-conjugated anti-polyhistidine antibody. Protein-peptide binding assays were applied successfully to (a) identifying the binding site on one component (represented by peptides) for another component (proteins), (b) precisely defining the "binding sequence," (c) acquiring information on the binding site in the partner protein, (d) investigating the effect of conformational changes in proteins on binding to peptides, (e) determining the effect of physicochemical modification of peptides on binding of proteins, and (f) identifying epitopes recognized by anti-oxidase component antibodies by binding of antibody to peptide arrays derived from the component.
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Affiliation(s)
- Edgar Pick
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
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9
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Nguyen GT, Green ER, Mecsas J. Neutrophils to the ROScue: Mechanisms of NADPH Oxidase Activation and Bacterial Resistance. Front Cell Infect Microbiol 2017; 7:373. [PMID: 28890882 PMCID: PMC5574878 DOI: 10.3389/fcimb.2017.00373] [Citation(s) in RCA: 430] [Impact Index Per Article: 61.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 08/02/2017] [Indexed: 12/16/2022] Open
Abstract
Reactive oxygen species (ROS) generated by NADPH oxidase play an important role in antimicrobial host defense and inflammation. Their deficiency in humans results in recurrent and severe bacterial infections, while their unregulated release leads to pathology from excessive inflammation. The release of high concentrations of ROS aids in clearance of invading bacteria. Localization of ROS release to phagosomes containing pathogens limits tissue damage. Host immune cells, like neutrophils, also known as PMNs, will release large amounts of ROS at the site of infection following the activation of surface receptors. The binding of ligands to G-protein-coupled receptors (GPCRs), toll-like receptors, and cytokine receptors can prime PMNs for a more robust response if additional signals are encountered. Meanwhile, activation of Fc and integrin directly induces high levels of ROS production. Additionally, GPCRs that bind to the bacterial-peptide analog fMLP, a neutrophil chemoattractant, can both prime cells and trigger low levels of ROS production. Engagement of these receptors initiates intracellular signaling pathways, resulting in activation of downstream effector proteins, assembly of the NADPH oxidase complex, and ultimately, the production of ROS by this complex. Within PMNs, ROS released by the NADPH oxidase complex can activate granular proteases and induce the formation of neutrophil extracellular traps (NETs). Additionally, ROS can cross the membranes of bacterial pathogens and damage their nucleic acids, proteins, and cell membranes. Consequently, in order to establish infections, bacterial pathogens employ various strategies to prevent restriction by PMN-derived ROS or downstream consequences of ROS production. Some pathogens are able to directly prevent the oxidative burst of phagocytes using secreted effector proteins or toxins that interfere with translocation of the NADPH oxidase complex or signaling pathways needed for its activation. Nonetheless, these pathogens often rely on repair and detoxifying proteins in addition to these secreted effectors and toxins in order to resist mammalian sources of ROS. This suggests that pathogens have both intrinsic and extrinsic mechanisms to avoid restriction by PMN-derived ROS. Here, we review mechanisms of oxidative burst in PMNs in response to bacterial infections, as well as the mechanisms by which bacterial pathogens thwart restriction by ROS to survive under conditions of oxidative stress.
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Affiliation(s)
- Giang T Nguyen
- Graduate Program in Immunology, Sackler School of Graduate Biomedical Sciences, Tufts UniversityBoston, MA, United States
| | - Erin R Green
- Department of Molecular Biology and Microbiology, Tufts University School of MedicineBoston, MA, United States
| | - Joan Mecsas
- Graduate Program in Immunology, Sackler School of Graduate Biomedical Sciences, Tufts UniversityBoston, MA, United States.,Department of Molecular Biology and Microbiology, Tufts University School of MedicineBoston, MA, United States
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10
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Cifuentes-Pagano ME, Meijles DN, Pagano PJ. Nox Inhibitors & Therapies: Rational Design of Peptidic and Small Molecule Inhibitors. Curr Pharm Des 2016; 21:6023-35. [PMID: 26510437 DOI: 10.2174/1381612821666151029112013] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Accepted: 10/27/2015] [Indexed: 12/15/2022]
Abstract
Oxidative stress-related diseases underlie many if not all of the major leading causes of death in United States and the Western World. Thus, enormous interest from both academia and pharmaceutical industry has been placed on the development of agents which attenuate oxidative stress. With that in mind, great efforts have been placed in the development of inhibitors of NADPH oxidase (Nox), the major enzymatic source of reactive oxygen species and oxidative stress in many cells and tissue. The regulation of a catalytically active Nox enzyme involves numerous protein-protein interactions which, in turn, afford numerous targets for inhibition of its activity. In this review, we will provide an updated overview of the available Nox inhibitors, both peptidic and small molecules, and discuss the body of data related to their possible mechanisms of action and specificity towards each of the various isoforms of Nox. Indeed, there have been some very notable successes. However, despite great commitment by many in the field, the need for efficacious and well-characterized, isoform-specific Nox inhibitors, essential for the treatment of major diseases as well as for delineating the contribution of a given Nox in physiological redox signalling, continues to grow.
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Affiliation(s)
| | | | - Patrick J Pagano
- Department of Pharmacology & Chemical Biology, Vascular Medicine Institute, University of Pittsburgh School of Medicine, Biomedical Science Tower, 12th Floor, Room E1247, 200 Lothrop St., Pittsburgh, PA 15261, USA.
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11
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Abstract
Since its discovery in 1999, a number of studies have evaluated the role of Nox1 NADPH oxidase in the cardiovascular system. Nox1 is activated in vascular cells in response to several different agonists, with its activity regulated at the transcriptional level as well as by NADPH oxidase complex formation, protein stabilization and post-translational modification. Nox1 has been shown to decrease the bioavailability of nitric oxide, transactivate the epidermal growth factor receptor, induce pro-inflammatory signalling, and promote cell migration and proliferation. Enhanced expression and activity of Nox1 under pathologic conditions results in excessive production of reactive oxygen species and dysregulated cellular function. Indeed, studies using genetic models of Nox1 deficiency or overexpression have revealed roles for Nox1 in the pathogenesis of cardiovascular diseases ranging from atherosclerosis to hypertension, restenosis and ischaemia/reperfusion injury. These data suggest that Nox1 is a potential therapeutic target for vascular disease, and drug development efforts are ongoing to identify a specific bioavailable inhibitor of Nox1.
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12
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Karimi G, Houée Levin C, Dagher MC, Baciou L, Bizouarn T. Assembly of phagocyte NADPH oxidase: A concerted binding process? Biochim Biophys Acta Gen Subj 2014; 1840:3277-83. [DOI: 10.1016/j.bbagen.2014.07.022] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2014] [Revised: 07/11/2014] [Accepted: 07/30/2014] [Indexed: 11/15/2022]
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Streeter J, Schickling BM, Jiang S, Stanic B, Thiel WH, Gakhar L, Houtman JCD, Miller FJ. Phosphorylation of Nox1 regulates association with NoxA1 activation domain. Circ Res 2014; 115:911-8. [PMID: 25228390 DOI: 10.1161/circresaha.115.304267] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
RATIONALE Activation of Nox1 initiates redox-dependent signaling events crucial in the pathogenesis of vascular disease. Selective targeting of Nox1 is an attractive potential therapy, but requires a better understanding of the molecular modifications controlling its activation. OBJECTIVE To determine whether posttranslational modifications of Nox1 regulate its activity in vascular cells. METHODS AND RESULTS We first found evidence that Nox1 is phosphorylated in multiple models of vascular disease. Next, studies using mass spectroscopy and a pharmacological inhibitor demonstrated that protein kinase C-beta1 mediates phosphorylation of Nox1 in response to tumor necrosis factor-α. siRNA-mediated silencing of protein kinase C-beta1 abolished tumor necrosis factor-α-mediated reactive oxygen species production and vascular smooth muscle cell migration. Site-directed mutagenesis and isothermal titration calorimetry indicated that protein kinase C-beta1 phosphorylates Nox1 at threonine 429. Moreover, Nox1 threonine 429 phosphorylation facilitated the association of Nox1 with the NoxA1 activation domain and was necessary for NADPH oxidase complex assembly, reactive oxygen species production, and vascular smooth muscle cell migration. CONCLUSIONS We conclude that protein kinase C-beta1 phosphorylation of threonine 429 regulates activation of Nox1 NADPH oxidase.
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Affiliation(s)
- Jennifer Streeter
- From the Departments of Internal Medicine (B.M.S., S.J., B.S., W.H.T., F.J.M.), Microbiology (J.C.D.H.), Anatomy and Cell Biology (J.S.), Biochemistry (L.G.), and Protein Crystallography Facility (L.G.), University of Iowa, Iowa City; and Veterans Affair Medical Center, Iowa City, IA (F.J.M.)
| | - Brandon M Schickling
- From the Departments of Internal Medicine (B.M.S., S.J., B.S., W.H.T., F.J.M.), Microbiology (J.C.D.H.), Anatomy and Cell Biology (J.S.), Biochemistry (L.G.), and Protein Crystallography Facility (L.G.), University of Iowa, Iowa City; and Veterans Affair Medical Center, Iowa City, IA (F.J.M.)
| | - Shuxia Jiang
- From the Departments of Internal Medicine (B.M.S., S.J., B.S., W.H.T., F.J.M.), Microbiology (J.C.D.H.), Anatomy and Cell Biology (J.S.), Biochemistry (L.G.), and Protein Crystallography Facility (L.G.), University of Iowa, Iowa City; and Veterans Affair Medical Center, Iowa City, IA (F.J.M.)
| | - Bojana Stanic
- From the Departments of Internal Medicine (B.M.S., S.J., B.S., W.H.T., F.J.M.), Microbiology (J.C.D.H.), Anatomy and Cell Biology (J.S.), Biochemistry (L.G.), and Protein Crystallography Facility (L.G.), University of Iowa, Iowa City; and Veterans Affair Medical Center, Iowa City, IA (F.J.M.)
| | - William H Thiel
- From the Departments of Internal Medicine (B.M.S., S.J., B.S., W.H.T., F.J.M.), Microbiology (J.C.D.H.), Anatomy and Cell Biology (J.S.), Biochemistry (L.G.), and Protein Crystallography Facility (L.G.), University of Iowa, Iowa City; and Veterans Affair Medical Center, Iowa City, IA (F.J.M.)
| | - Lokesh Gakhar
- From the Departments of Internal Medicine (B.M.S., S.J., B.S., W.H.T., F.J.M.), Microbiology (J.C.D.H.), Anatomy and Cell Biology (J.S.), Biochemistry (L.G.), and Protein Crystallography Facility (L.G.), University of Iowa, Iowa City; and Veterans Affair Medical Center, Iowa City, IA (F.J.M.)
| | - Jon C D Houtman
- From the Departments of Internal Medicine (B.M.S., S.J., B.S., W.H.T., F.J.M.), Microbiology (J.C.D.H.), Anatomy and Cell Biology (J.S.), Biochemistry (L.G.), and Protein Crystallography Facility (L.G.), University of Iowa, Iowa City; and Veterans Affair Medical Center, Iowa City, IA (F.J.M.)
| | - Francis J Miller
- From the Departments of Internal Medicine (B.M.S., S.J., B.S., W.H.T., F.J.M.), Microbiology (J.C.D.H.), Anatomy and Cell Biology (J.S.), Biochemistry (L.G.), and Protein Crystallography Facility (L.G.), University of Iowa, Iowa City; and Veterans Affair Medical Center, Iowa City, IA (F.J.M.).
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14
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Matono R, Miyano K, Kiyohara T, Sumimoto H. Arachidonic acid induces direct interaction of the p67(phox)-Rac complex with the phagocyte oxidase Nox2, leading to superoxide production. J Biol Chem 2014; 289:24874-84. [PMID: 25056956 DOI: 10.1074/jbc.m114.581785] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The phagocyte NADPH oxidase Nox2, heterodimerized with p22(phox) in the membrane, is dormant in resting cells but becomes activated upon cell stimulation to produce superoxide, a precursor of microbicidal oxidants. Nox2 activation requires two switches to be turned on simultaneously: a conformational change of the cytosolic protein p47(phox) and GDP/GTP exchange on the small GTPase Rac. These proteins, in an active form, bind to their respective targets, p22(phox) and p67(phox), leading to productive oxidase assembly at the membrane. Although arachidonic acid (AA) efficiently activates Nox2 both in vivo and in vitro, the mechanism has not been fully understood, except that AA induces p47(phox) conformational change. Here we show that AA elicits GDP-to-GTP exchange on Rac at the cellular level, consistent with its role as a potent Nox2 activator. However, even when constitutively active forms of p47(phox) and Rac1 are both expressed in HeLa cells, superoxide production by Nox2 is scarcely induced in the absence of AA. These active proteins also fail to effectively activate Nox2 in a cell-free reconstituted system without AA. Without affecting Rac-GTP binding to p67(phox), AA induces the direct interaction of Rac-GTP-bound p67(phox) with the C-terminal cytosolic region of Nox2. p67(phox)-Rac-Nox2 assembly and superoxide production are both abrogated by alanine substitution for Tyr-198, Leu-199, and Val-204 in the p67(phox) activation domain that localizes the C-terminal to the Rac-binding domain. Thus the "third" switch (AA-inducible interaction of p67(phox)·Rac-GTP with Nox2) is required to be turned on at the same time for Nox2 activation.
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Affiliation(s)
- Rumi Matono
- From the Department of Biochemistry, Kyushu University Graduate School of Medical Sciences, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Kei Miyano
- From the Department of Biochemistry, Kyushu University Graduate School of Medical Sciences, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Takuya Kiyohara
- From the Department of Biochemistry, Kyushu University Graduate School of Medical Sciences, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Hideki Sumimoto
- From the Department of Biochemistry, Kyushu University Graduate School of Medical Sciences, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
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Roos D, van Buul JD, Tool ATJ, Matute JD, Marchal CM, Hayee B, Köker MY, de Boer M, van Leeuwen K, Segal AW, Pick E, Dinauer MC. Two CGD Families with a Hypomorphic Mutation in the Activation Domain of p67 phox. JOURNAL OF CLINICAL & CELLULAR IMMUNOLOGY 2014; 5:1000231. [PMID: 25937994 PMCID: PMC4414043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
STUDY BACKGROUND Chronic granulomatous Disease (CGD) is a rare immunodeficiency caused by a defect in the leukocyte NADPH oxidase. This enzyme generates superoxide, which is needed for the killing of bacteria and fungi by phagocytic leukocytes. Most CGD patients have mutations in CYBB, the X-linked gene that encodes gp91phox, the catalytic subunit of the leukocyte NADPH oxidase. We report here three autosomal recessive CGD patients from two families with a homozygous mutation in NCF2, the gene that encodes p67phox, the activator subunit of the NADPH oxidase. METHODS Leukocyte NADPH oxidase activity, expression of oxidase components and gene sequences were measured with standard methods. The mutation found in the patients' NCF2 gene was expressed as Ala202Val-p67phox in K562 cells to measure its effect on NADPH oxidase activity. Translocation of the mutated p67phox from the cytosol of the patients' neutrophils to the plasma membrane was measured by confocal microscopy and by Western blotting after membrane purification. RESULTS The exceptional feature of the A67 CGD patients reported here is that the p.Ala202Val mutation in the activation domain of p67phox was clearly hypomorphic: substantial expression of p67phox protein was noted and the NADPH oxidase activity in the neutrophils of the patients was 20-70% of normal, dependent on the stimulus used to activate the cells. The extent of Ala202Val-p67phox translocation to the plasma membrane during cell activation was also stimulus dependent. Ala202Val-p67phox in K562 cells mediated only about 3% of normal oxidase activity compared to cells transfected with the wild-type p67phox. CONCLUSION The mutation found in NCF2 is the cause of the decreased NADPH oxidase activity and the (mild) clinical problems of the patients. We propose that the p.Ala202Val mutation has changed the conformation of the activation domain of p67phox, resulting in reduced activation of gp91phox.
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Affiliation(s)
- Dirk Roos
- Sanquin Research and Landsteiner Laboratory, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
| | - Jaap D van Buul
- Sanquin Research and Landsteiner Laboratory, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
| | - Anton TJ Tool
- Sanquin Research and Landsteiner Laboratory, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
| | - Juan D Matute
- Departments of Pediatrics (Hematology/Oncology), Microbiology/Immunology, and Medical and Molecular Genetics, Riley Hospital for Children, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Christophe M Marchal
- Departments of Pediatrics (Hematology/Oncology), Microbiology/Immunology, and Medical and Molecular Genetics, Riley Hospital for Children, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Bu’Hussain Hayee
- Department of Medicine, University College London, London, United Kingdom
| | - M Yavuz Köker
- Department of Immunology and Immunology Laboratory, Faculty of Medicine, University of Erciyes, Kayseri, Turkey
| | - Martin de Boer
- Sanquin Research and Landsteiner Laboratory, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
| | - Karin van Leeuwen
- Sanquin Research and Landsteiner Laboratory, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
| | - Anthony W Segal
- Department of Medicine, University College London, London, United Kingdom
| | - Edgar Pick
- Julius Friedrich Cohnheim Laboratory of Phagocyte Research, Sackler School of Medicine, Tel Aviv University, Israel
| | - Mary C Dinauer
- Departments of Pediatrics (Hematology/Oncology), Microbiology/Immunology, and Medical and Molecular Genetics, Riley Hospital for Children, Indiana University School of Medicine, Indianapolis, IN, USA
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Miyano K, Sumimoto H. N-linked glycosylation of the superoxide-producing NADPH oxidase Nox1. Biochem Biophys Res Commun 2014; 443:1060-5. [DOI: 10.1016/j.bbrc.2013.12.086] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 12/17/2013] [Indexed: 10/25/2022]
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17
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Abstract
The superoxide (O2 (∙-))-generating NADPH oxidase complex of phagocytes comprises a membrane-imbedded heterodimeric flavocytochrome, known as cytochrome b 558 (consisting of Nox2 and p22 (phox) ) and four cytosolic regulatory proteins, p47 (phox) , p67 (phox) , p40 (phox) , and the small GTPase Rac. Under physiological conditions, in the resting phagocyte, O2 (∙-) generation is initiated by engagement of membrane receptors by a variety of stimuli, followed by specific signal transduction sequences leading to the translocation of the cytosolic components to the membrane and their association with the cytochrome. A consequent conformational change in Nox2 initiates the electron "flow" along a redox gradient, from NADPH to oxygen, leading to the one-electron reduction of molecular oxygen to O2 (∙-). Methodological difficulties in the dissection of this complex mechanism led to the design "cell-free" systems (also known as "broken cells" or in vitro systems). In these, membrane receptor stimulation and all or part of the signal transduction sequence are missing, the accent being placed on the actual process of "NADPH oxidase assembly," thus on the formation of the complex between cytochrome b 558 and the cytosolic components and the resulting O2 (∙-) generation. Cell-free assays consist of a mixture of the individual components of the NADPH oxidase complex, derived from resting phagocytes or in the form of purified recombinant proteins, exposed in vitro to an activating agent (distinct from and unrelated to whole cell stimulants), in the presence of NADPH and oxygen. Activation is commonly quantified by measuring the primary product of the reaction, O2 (∙-), trapped immediately after its generation by an appropriate acceptor in a kinetic assay, permitting the calculation of the linear rate of O2 (∙-) production, but numerous variations exist, based on the assessment of reaction products or the consumption of substrates. Cell-free assays played a paramount role in the identification and characterization of the components of the NADPH oxidase complex, the deciphering of the mechanisms of assembly, the search for inhibitory drugs, and the diagnosis of various forms of chronic granulomatous disease (CGD).
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Affiliation(s)
- Edgar Pick
- The Julius Friedrich Cohnheim-Minerva Center for Phagocyte Research and the Ela Kodesz Institute of Host Defense against Infectious Diseases, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
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18
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Ranayhossaini DJ, Rodriguez AI, Sahoo S, Chen BB, Mallampalli RK, Kelley EE, Csanyi G, Gladwin MT, Romero G, Pagano PJ. Selective recapitulation of conserved and nonconserved regions of putative NOXA1 protein activation domain confers isoform-specific inhibition of Nox1 oxidase and attenuation of endothelial cell migration. J Biol Chem 2013; 288:36437-50. [PMID: 24187133 PMCID: PMC3868757 DOI: 10.1074/jbc.m113.521344] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Indexed: 11/06/2022] Open
Abstract
Excessive vascular and colon epithelial reactive oxygen species production by NADPH oxidase isoform 1 (Nox1) has been implicated in a number of disease states, including hypertension, atherosclerosis, and neoplasia. A peptide that mimics a putative activation domain of the Nox1 activator subunit NOXA1 (NOXA1 docking sequence, also known as NoxA1ds) potently inhibited Nox1-derived superoxide anion (O2·-) production in a reconstituted Nox1 cell-free system, with no effect on Nox2-, Nox4-, Nox5-, or xanthine oxidase-derived reactive oxygen species production as measured by cytochrome c reduction, Amplex Red fluorescence, and electron paramagnetic resonance. The ability of NoxA1ds to cross the plasma membrane was tested by confocal microscopy in a human colon cancer cell line exclusively expressing Nox1 (HT-29) using FITC-labeled NoxA1ds. NoxA1ds significantly inhibited whole HT-29 carcinoma cell-derived O2·- generation. ELISA and fluorescence recovery after photobleaching experiments indicate that NoxA1ds, but not its scrambled control, binds Nox1. FRET experiments conducted using Nox1-YFP and NOXA1-CFP illustrate that NoxA1ds disrupts the binding interaction between Nox1 and NOXA1, whereas a control peptide did not. Moreover, hypoxia-induced human pulmonary artery endothelial cell O2·- production was completely inhibited by NoxA1ds. Human pulmonary artery endothelial cell migration under hypoxic conditions was also reduced by pretreatment with NoxA1ds. Our data indicate that a peptide recapitulating a putative activation subdomain of NOXA1 (NoxA1ds) is a highly efficacious and selective inhibitor of Nox1 activity and establishes a critical interaction site for Nox1-NOXA1 binding required for enzyme activation.
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Affiliation(s)
- Daniel J. Ranayhossaini
- From the Vascular Medicine Institute and
- Departments of Pharmacology and Chemical Biology and
| | - Andres I. Rodriguez
- From the Vascular Medicine Institute and
- Departments of Pharmacology and Chemical Biology and
| | | | - Beibei B. Chen
- Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15261 and
| | - Rama K. Mallampalli
- Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15261 and
- the Medical Specialty Service Line, Veterans Affairs Pittsburgh Healthcare System, Pittsburgh, Pennsylvania 15240
| | - Eric E. Kelley
- From the Vascular Medicine Institute and
- Departments of Pharmacology and Chemical Biology and
| | - Gabor Csanyi
- From the Vascular Medicine Institute and
- Departments of Pharmacology and Chemical Biology and
| | - Mark T. Gladwin
- From the Vascular Medicine Institute and
- Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15261 and
| | | | - Patrick J. Pagano
- From the Vascular Medicine Institute and
- Departments of Pharmacology and Chemical Biology and
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Kawano M, Ishii R, Yoshioka Y, Fukuda T, Tamura M. C-terminal truncation of Noxa1 greatly enhances its ability to activate Nox2 in a pure reconstitution system. Arch Biochem Biophys 2013; 538:164-70. [PMID: 24008014 DOI: 10.1016/j.abb.2013.08.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Revised: 08/27/2013] [Accepted: 08/28/2013] [Indexed: 12/20/2022]
Abstract
Noxa1 activates Nox2 together with Noxo1 and Rac in a pure reconstitution system, but the resulting activity is considerably lower than that induced by p67(phox) and p47(phox). In this study, we found that C-terminal-truncated forms of Noxa1 exhibited higher activities than full-length Noxa1. Of the truncations examined, Noxa1(1-225) showed the highest ability for activation. Kinetic studies revealed that Noxa1(1-225) had a threefold higher Vmax value than full-length Noxa1 with a similar EC50 value. The affinities of Noxo1 and RacQ61L were not much altered by the truncation. Conversely, the affinity of FAD for the Nox2 complex was enhanced after the truncation. In the absence of Noxo1, Noxa1(1-225) showed much higher activity with a lower EC50 than full-length Noxa1. Noxa1(1-225) showed comparable activity to that of p67(phox) with either Noxo1 or p47(phox), although the stability was lower than that with p67(phox) and p47(phox). These findings indicate that the role of the C-terminal half of Noxa1 is autoinhibition. The data suggest a two-step autoinhibition mechanism, comprising self-masking to interrupt the binding to the oxidase, and holding of the activation domain in a suboptimal position to the oxidase. This study reveals that when both types of inhibition are released, Noxa1 achieves high-level superoxide production.
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Affiliation(s)
- Masahito Kawano
- Department of Applied Chemistry, Graduate School of Science and Engineering, Ehime University, 3 Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan
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Interaction of NuMA protein with the kinesin Eg5: its possible role in bipolar spindle assembly and chromosome alignment. Biochem J 2013; 451:195-204. [DOI: 10.1042/bj20121447] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Bipolar spindle assembly in mitotic cells is a prerequisite to ensure correct alignment of chromosomes for their segregation to each daughter cell; spindle microtubules are tethered at plus ends to chromosomes and focused at minus ends to either of the two spindle poles. NuMA (nuclear mitotic apparatus protein) is present solely in the nucleus in interphase cells, but relocalizes during mitosis to the spindle poles to play a crucial role in spindle assembly via focusing spindle microtubules to each pole. In the present study we show that the kinesin-5 family motor Eg5 is a protein that directly interacts with NuMA, using a proteomics approach and various binding assays both in vivo and in vitro. During mitosis Eg5 appears to interact with NuMA in the vicinity of the spindle poles, whereas the interaction does not occur in interphase cells, where Eg5 is distributed throughout the cytoplasm but NuMA exclusively localizes to the nucleus. Slight, but significant, depletion of Eg5 in HeLa cells by RNA interference results in formation of less-focused spindle poles with misaligned chromosomes in metaphase; these phenotypes are similar to those induced by depletion of NuMA. Since NuMA is less accumulated at the spindle poles in Eg5-depleted cells, Eg5 probably contributes to spindle assembly via regulating NuMA localization. Furthermore, depletion of cytoplasmic dynein induces mislocalization of NuMA and phenotypes similar to those observed in NuMA-depleted cells, without affecting Eg5 localization to the spindles. Thus dynein appears to control NuMA function in conjunction with Eg5.
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21
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Abstract
Rac, a member of the Rho family small GTPases, plays a crucial role in activation of Nox family NADPH oxidases in animals, enzymes dedicated to production of reactive oxygen species such as superoxide. The phagocyte oxidase Nox2, crucial for microbicidal activity during phagocytosis, is activated in a manner completely dependent on Rac. Rac in the GTP-bound form directly binds to the oxidase activator p67( phox ), which in turn interacts with Nox2, leading to superoxide production. Rac also participates in activation of the nonphagocytic oxidase Nox1; in this case, GTP-bound Rac functions by interacting with Noxa1, a p67( phox )-related protein that is required for Nox1 activation. On the other hand, in the presence of either p67( phox ) or Noxa1, Rac facilitates superoxide production by Nox3, which is responsible in the inner ear for formation of otoconia, tiny mineralized structures that are required for sensing balance and gravity. All the three mammalian homologs of Rac (Rac1, Rac2, and Rac3), but not Cdc42 or RhoA, are capable of serving as an activator of Nox1-3. Here, we describe methods for the assay of Rac binding to p67( phox ) and Noxa1 and for the reconstitution of Rac-dependent Nox activity in cell-free and whole-cell systems.
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