scholarly journals Membrane Dynamics and Organization of the Phagocyte NADPH Oxidase in PLB-985 Cells

2020 ◽  
Vol 8 ◽  
Author(s):  
Jérémy Joly ◽  
Elodie Hudik ◽  
Sandrine Lecart ◽  
Dirk Roos ◽  
Paul Verkuijlen ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Nadph Oxidase ◽  
Proteolytic Enzymes ◽  
Super Resolution ◽  
Membrane Dynamics ◽  
Small Gtpase ◽  
Human Neutrophils ◽  
Number Of Clusters ◽  
Phagocyte Nadph Oxidase ◽  
Phagosomal Membrane

Neutrophils are the first cells recruited at the site of infections, where they phagocytose the pathogens. Inside the phagosome, pathogens are killed by proteolytic enzymes that are delivered to the phagosome following granule fusion, and by reactive oxygen species (ROS) produced by the NADPH oxidase. The NADPH oxidase complex comprises membrane proteins (NOX2 and p22phox), cytoplasmic subunits (p67phox, p47phox, and p40phox) and the small GTPase Rac. These subunits assemble at the phagosomal membrane upon phagocytosis. In resting neutrophils the catalytic subunit NOX2 is mainly present at the plasma membrane and in the specific granules. We show here that NOX2 is also present in early and recycling endosomes in human neutrophils and in the neutrophil-like cell line PLB-985 expressing GFP-NOX2. In the latter cells, an increase in NOX2 at the phagosomal membrane was detected by live-imaging after phagosome closure, probably due to fusion of endosomes with the phagosome. Using super-resolution microscopy in PLB-985 WT cells, we observed that NOX2 forms discrete clusters in the plasma membrane. The number of clusters increased during frustrated phagocytosis. In PLB-985NCF1ΔGT cells that lack p47phox and do not assemble a functional NADPH oxidase, the number of clusters remained stable during phagocytosis. Our data suggest a role for p47phox and possibly ROS production in NOX2 recruitment at the phagosome.

scholarly journals Consequences of the constitutive NOX2 activity in living cells: cytosol acidification, apoptosis, and localized lipid peroxidation

2021 ◽  
Author(s):  
Hana Valenta ◽  
Sophie Dupré-Crochet ◽  
Tania Bizouarn ◽  
Laura Baciou ◽  
Oliver Nüsse ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Nadph Oxidase ◽  
Living Cells ◽  
Small Gtpase ◽  
Activation Mechanism ◽  
Cell Physiology ◽  
List Type ◽  
Catalytic Core ◽  
Cytosolic Proteins ◽  
Phagocyte Nadph Oxidase

ABSTRACTThe phagocyte NADPH oxidase (NOX2) is a key enzyme of the innate immune system generating superoxide anions (O2•−), precursors of reactive oxygen species. The NOX2 protein complex is composed of six subunits: two membrane proteins (gp91phox and p22phox) forming the catalytic core, three cytosolic proteins (p67phox, p47phox and p40phox) and a small GTPase Rac. The sophisticated activation mechanism of the NADPH oxidase relies on the assembly of cytosolic subunits with the membrane-bound components. A chimeric protein, called ‘Trimera’, composed of the essential domains of the cytosolic proteins p47phox (aa 1-286), p67phox (aa 1-212) and full-length Rac1Q61L, enables a constitutive and robust NOX2 activity in cells without the need of any stimulus. We employed Trimera as a single activating protein of the phagocyte NADPH oxidase in living cells and examined the consequences on the cell physiology of this continuous and long-term NOX activity. We showed that the sustained high level of NOX activity causes acidification of the intracellular pH, triggers apoptosis and leads to local peroxidation of lipids in the membrane. These local damages to the membrane correlate with the strong tendency of the Trimera to clusterize in the plasma membrane observed by FRET-FLIM microscopy.HighlightsTrimera is a tool to trigger a continuous ROS production in living cellsContinuous NOX2 activity causes cytosol acidification and apoptosisROS overproduction leads to localized oxidation of the membrane lipidsTrimera tends to clusterize in the plasma membrane of COSNOX and COS-7 cells

scholarly journals Involvement of p40phox in activation of phagocyte NADPH oxidase through association of its carboxyl-terminal, but not its amino-terminal, with p67phox.

1996 ◽  
Vol 184 (3) ◽  
pp. 893-902 ◽  
Author(s):  
S Tsunawaki ◽  
S Kagara ◽  
K Yoshikawa ◽  
L S Yoshida ◽  
T Kuratsuji ◽  
...  
Keyword(s):  
Nadph Oxidase ◽  
Inhibitory Effect ◽  
Human Neutrophils ◽  
Resting Cells ◽  
Amino Terminal ◽  
Src Homology 3 ◽  
Phagocyte Nadph Oxidase ◽  
A Cell ◽  
Src Homology ◽  
Tight Association

Phagocyte NADPH oxidase, dormant in resting cells, is activated upon cell stimulation to produce superoxide anion, a precursor of microbicidal oxidants. Active NADPH oxidase is found on the membrane as an enzyme complex, composed of membrane-integrated cytochrome b558 (gp91phox and p22phox subunits) and two cytosolic factors (p47phox and p67phox), each of the latter containing two src homology 3 (SH3) domains. Recently, we radioactively identified a third cytosolic factor, p40phox, as a molecule that associates with p67phox in human neutrophils. Although it has been found that this p40phox protein is defective in patients with chronic granulomatous disease (CGD) who lack p67phox, evidence to functionally relate it to the NADPH oxidase system has hitherto been lacking. In this study, we raised separate antibodies against both the COOH- and NH2-terminal polypeptides of p40phox as well as against the COOH-terminal polypeptide of p67phox to examine the mode of interaction between p40phox and p67phox in a complex. The antibody against the COOH terminus of p67phox was able to communoprecipitate p40phox in conjunction with p67phox itself as was expected. Very interestingly, however, the antibody against the COOH terminus of p40phox completely dissociated the p67phox molecule from the p40phox-p67phox complex unit without any detectable coimmunoprecipitation of p67phox, despite their tight association, whereas that against the NH2 terminus of p40phox had absolutely no dissociation effect. Similar results were found regarding their effects on the O2-generating ability of cytosol in a cell-free activation system, i.e., inhibition was noted with the COOH terminus antibody but not with that for the NH2 terminus of p40phox. However, this dissociation did not affect the translocation of the cytosolic components including p47phox to the membrane. Once the NADPH oxidase was activated, the antibody for the COOH terminus did not show any inhibitory effect on catalysis by the activated enzyme. The stimulators of NADPH oxidase, MA and SDS, did not dissociate the p40phox-p67phox complex. These results provide the first demonstration that p40phox is practically involved in the activation of NADPH oxidase through the association of its COOH-terminal, but not its NH2-terminal, with p67phox.

scholarly journals STED super-resolution imaging of membrane packing and dynamics by exchangeable polarity-sensitive dyes

2021 ◽  
Author(s):  
Pablo Carravilla ◽  
Anindita Dasgupta ◽  
Gaukhar Zhurgenbayeva ◽  
Dmytro I. Danylchuk ◽  
Andrey S. Klymchenko ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Real Time ◽  
Spatial Resolution ◽  
Super Resolution ◽  
Membrane Dynamics ◽  
Live Cell ◽  
Stimulated Emission ◽  
Sted Microscopy ◽  
Temporal And Spatial ◽  
Polarity Sensitive

Understanding the plasma membrane nano-scale organisation and dynamics in living cells requires microscopy techniques with high temporal and spatial resolution and long acquisition times, that also allow for the quantification of membrane biophysical properties such as lipid ordering. Among the most popular super-resolution techniques, stimulated emission depletion (STED) microscopy offers one of the highest temporal resolution, ultimately defined by the scanning speed. However, monitoring live processes using STED microscopy is significantly limited by photobleaching, which recently has been circumvented by exchangeable membrane dyes that only temporarily reside in the membrane. Here, we show that NR4A, a polarity-sensitive exchangeable plasma membrane probe based on Nile Red, permits the super-resolved quantification of membrane biophysical parameters in real time with high temporal and spatial resolution as well as long acquisition times. The potential of this polarity-sensitive exchangeable dyes is showcased by live-cell real-time 3D-STED recordings of bleb formation and lipid exchange during membrane fusion, as well as by STED-fluorescence correlation spectroscopy (STED-FCS) experiments for the simultaneous quantification of membrane dynamics and lipid packing, which correlate in model and live-cell membranes.

A region N-terminal to the tandem SH3 domain of p47phox plays a crucial role in the activation of the phagocyte NADPH oxidase

2009 ◽  
Vol 419 (2) ◽  
pp. 329-338 ◽  
Author(s):  
Masahiko Taura ◽  
Kei Miyano ◽  
Reiko Minakami ◽  
Sachiko Kamakura ◽  
Ryu Takeya ◽  
...  
Keyword(s):  
Nadph Oxidase ◽  
Crucial Role ◽  
Sh3 Domain ◽  
Small Gtpase ◽  
Dependent Manner ◽  
Wild Type ◽  
Catalytic Core ◽  
Membrane Recruitment ◽  
Phagocyte Nadph Oxidase ◽  
Isoleucine Residue

The superoxide-producing NADPH oxidase in phagocytes is crucial for host defence; its catalytic core is the membrane-integrated protein gp91phox [also known as Nox2 (NADPH oxidase 2)], which forms a stable heterodimer with p22phox. Activation of the oxidase requires membrane translocation of the three cytosolic proteins p47phox, p67phox and the small GTPase Rac. At the membrane, these proteins assemble with the gp91phox–p22phox heterodimer and induce a conformational change of gp91phox, leading to superoxide production. p47phox translocates to membranes using its two tandemly arranged SH3 domains, which directly interact with p22phox, whereas p67phox is recruited in a p47phox-dependent manner. In the present study, we show that a short region N-terminal to the bis-SH3 domain is required for activation of the phagocyte NADPH oxidase. Alanine substitution for Ile152 in this region, a residue that is completely conserved during evolution, results in a loss of the ability to activate the oxidase; and the replacement of Thr153 also prevents oxidase activation, but to a lesser extent. In addition, the corresponding isoleucine residue (Ile155) of the p47phox homologue Noxo1 (Nox organizer 1) participates in the activation of non-phagocytic oxidases, such as Nox1 and Nox3. The I152A substitution in p47phox, however, does not affect its interaction with p22phox or with p67phox. Consistent with this, a mutant p47phox (I152A), as well as the wild-type protein, is targeted upon cell stimulation to membranes, and membrane recruitment of p67phox and Rac normally occurs in p47phox (I152A)-expressing cells. Thus the Ile152-containing region of p47phox plays a crucial role in oxidase activation, probably by functioning at a process after oxidase assembly.

Nox4 mediates angiotensin II-induced activation of Akt/protein kinase B in mesangial cells

2003 ◽  
Vol 285 (2) ◽  
pp. F219-F229 ◽  
Author(s):  
Yves Gorin ◽  
Jill M. Ricono ◽  
Nam-Ho Kim ◽  
Basant Bhandari ◽  
Goutam Ghosh Choudhury ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Protein Kinase ◽  
Nadph Oxidase ◽  
Mesangial Cells ◽  
Protein Kinase B ◽  
Small Gtpase ◽  
Dominant Negative ◽  
Ros Generation ◽  
Ang Ii ◽  
Phagocyte Nadph Oxidase

ANG II induces protein synthesis through the serine-threonine kinase Akt/protein kinase B (PKB) in mesangial cells (MCs). The mechanism(s) of activation of Akt/PKB particularly by G protein-coupled receptors, however, is not well characterized. We explored the role of the small GTPase Rac1, a component of the phagocyte NADPH oxidase, and the gp91 phox homologue Nox4/Renox in this signaling pathway. ANG II causes rapid activation of Rac1, an effect abrogated by phospholipase A2 inhibition and mimicked by arachidonic acid (AA). Northern blot analysis revealed high levels of Nox4 transcript in MCs and transfection with antisense (AS) oligonucleotides for Nox4 markedly decreased NADPH-dependent reactive oxygen species (ROS)-producing activity. Dominant negative Rac1 (N17Rac1) as well as AS Nox4 inhibited ROS generation in response to ANG II and AA, whereas constitutively active Rac1 stimulated ROS formation. Moreover, N17Rac1 blocked stimulation of NADPH oxidase activity by AA. N17Rac1 or AS Nox4 abolished ANG II- or AA-induced activation of the hypertrophic kinase Akt/PKB. In addition, AS Nox4 inhibited ANG II-induced protein synthesis. These data provide the first evidence that activation by AA of a Rac1-regulated, Nox4-based NAD(P)H oxidase and subsequent generation of ROS mediate the effect of ANG II on Akt/PKB activation and protein synthesis in MCs.

scholarly journals Live-Cell Super-resolution Reveals F-Actin and Plasma Membrane Dynamics at the T Cell Synapse

2017 ◽  
Vol 112 (8) ◽  
pp. 1703-1713 ◽  
Author(s):  
George W. Ashdown ◽  
Garth L. Burn ◽  
David J. Williamson ◽  
Elvis Pandžić ◽  
Ruby Peters ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
T Cell ◽  
Super Resolution ◽  
Membrane Dynamics ◽  
Live Cell ◽  
Cell Synapse

scholarly journals Relationship between phosphorylation and translocation to the plasma membrane of p47phox and p67phox and activation of the NADPH oxidase in normal and Ca2+-depleted human neutrophils

1993 ◽  
Vol 290 (1) ◽  
pp. 173-178 ◽  
Author(s):  
S Dusi ◽  
V Della Bianca ◽  
M Grzeskowiak ◽  
F Rossi
Keyword(s):  
Plasma Membrane ◽  
Nadph Oxidase ◽  
Phorbol Esters ◽  
Second Messengers ◽  
Human Neutrophils ◽  
Phosphorylated Proteins ◽  
Kinase C ◽  
Activated State ◽  
Phagocyte Oxidase ◽  
Hydrolysis Of

Stimulation of neutrophils with different agonists activates a latent multicomponent NADPH oxidase that reduces molecular oxygen to superoxide anion. Evidence has accumulated that phosphorylation of p47phox (the 47 kDa cytosolic phagocyte oxidase factor) and translocation of the two cytosolic components p47phox and p67phox are essential steps in the activation of NADPH oxidase in response to phorbol esters. We analysed the relationships between activation of the NADPH oxidase and phosphorylation and translocation of p47phox and p67phox in normal and Ca(2+)-depleted neutrophils stimulated by the receptor-mediated agonists formyl-methionyl-leucyl-phenylalanine and concanavalin A. The results produced the following conclusions: (1) Translocation of p47phox and p67phox is an essential mechanism for activation of the NADPH oxidase. (2) A continuous translocation of p47phox and p67phox is necessary to maintain the NADPH oxidase in an activated state. (3) Only a fraction of p47phox and p67phox translocated to the plasma membrane is functional for the activation of the oxidase. (4) Translocation is independent of protein kinase C, and is linked to transmembrane signalling involving Ca2+ transients and production of lipidic second messengers. However, under some conditions, such as in Ca(2+)-depleted neutrophils, translocation can also occur independently of signalling pathways involving production of second messengers from hydrolysis of phospholipids and Ca2+ transients. (5) Phosphorylation of p47phox and p67phox can be quantitatively dissociated from translocation, as staurosporine markedly inhibits phosphorylation but not translocation. (6) The activity of NADPH oxidase is not correlated with the amounts of the phosphorylated proteins present in the plasma membrane.

scholarly journals In vitro and in vivo modulation of NADPH-oxidase activity and reactive oxygen species production in human neutrophils by alpha-1 antitrypsin

2021 ◽  
pp. 00234-2021
Author(s):  
Padraig Hawkins ◽  
Thomas McEnery ◽  
Claudie Gabillard-Lefort ◽  
David A Bergin ◽  
Bader Alfawaz ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Plasma Membrane ◽  
Nadph Oxidase ◽  
Ex Vivo ◽  
Human Neutrophils ◽  
Driving Mechanism ◽  
Increased Risk ◽  
Alpha 1 Antitrypsin

Oxidative stress from innate immune cells is a driving mechanism that underlies COPD pathogenesis. Individuals with alpha-1 antitrypsin (AAT) deficiency (AATD) have a dramatically increased risk of developing COPD. To understand this further, the aim of this study was to investigate whether AATD presents with altered neutrophil NADPH-oxidase activation, due to the specific lack of plasma AAT. Experiments were performed using circulating neutrophils isolated from healthy controls and individuals with AATD. Superoxide anion (O2−) production was determined from the rate of reduction of cytochrome c. Quantification of membrane NADPH-oxidase subunits was performed by mass spectrometry and western blot analysis. The clinical significance of our in vitro findings were assessed in patients with AATD and severe COPD receiving intravenous AAT replacement therapy. In vitro, AAT significantly inhibited O2− production by stimulated neutrophils and suppressed receptor stimulation of cyclic adenosimonophosphate (cAMP) and extracellular-signal regulated kinase (ERK)1/2 phosphorylation. In addition, AAT reduced plasma membrane translocation of cytosolic phox components of the NADPH-oxidase. Ex vivo, AATD neutrophils demonstrated increased plasma membrane associated p67phox and p47phox and significantly increased O2− production. The described variance in phox protein membrane assembly was resolved post AAT augmentation therapy in vivo, the effects of which significantly reduced AATD neutrophil O2− production to that of healthy control cells. These results expand our knowledge on the mechanism of neutrophil driven airways disease associated with AATD. Therapeutic AAT augmentation modified neutrophil NADPH-oxidase assembly and ROS production, with implications for clinical use in conditions in which oxidative stress plays a pathogenic role.

Super-resolution optical microscopy of lipid plasma membrane dynamics

2015 ◽  
Vol 57 ◽  
pp. 69-80 ◽  
Author(s):  
Christian Eggeling
Keyword(s):  
Plasma Membrane ◽  
Protein Interactions ◽  
Molecular Diffusion ◽  
Super Resolution ◽  
Optical Microscope ◽  
Membrane Dynamics ◽  
Correlation Spectroscopy ◽  
Stimulated Emission ◽  
Diffusion Dynamics ◽  
Lipid Protein Interactions

Plasma membrane dynamics are an important ruler of cellular activity, particularly through the interaction and diffusion dynamics of membrane-embedded proteins and lipids. FCS (fluorescence correlation spectroscopy) on an optical (confocal) microscope is a popular tool for investigating such dynamics. Unfortunately, its full applicability is constrained by the limited spatial resolution of a conventional optical microscope. The present chapter depicts the combination of optical super-resolution STED (stimulated emission depletion) microscopy with FCS, and why it is an important tool for investigating molecular membrane dynamics in living cells. Compared with conventional FCS, the STED-FCS approach demonstrates an improved possibility to distinguish free from anomalous molecular diffusion, and thus to give new insights into lipid–protein interactions and the traditional lipid ‘raft’ theory.

Sign in / Sign up

Export Citation Format

Share Document