scholarly journals The enzymic reduction and kinetics of oxidation of cytochrome b.245 of neutrophils

1982 ◽  
Vol 204 (2) ◽  
pp. 479-485 ◽  
Author(s):  
A R Cross ◽  
F K Higson ◽  
O T G Jones ◽  
A M Harper ◽  
A W Segal
Keyword(s):  
Plasma Membrane ◽  
Cytochrome B ◽  
Room Temperature ◽  
Human Neutrophils ◽  
Polymorphonuclear Leucocytes ◽  
Myristate Acetate ◽  
Kinetics Of Oxidation ◽  
Granule Fraction ◽  
Kinetics Of ◽  
Stimulation Of

1. The absorption coefficient of human neutrophil plasma-membrane reduced-minus-oxidized cytochrome b-245 was determined [delta epsilon (mM; 559-540 nm) = 21.6 cm-1]. 2. Neutrophil polymorphonuclear leucocytes (neutrophils) were prepared from human, ox, horse and pig blood. In each case plasma-membrane fractions were found to contain low-potential cytochrome b. When membranes from horse neutrophils were incubated anaerobically with either NADH or NADPH the cytochrome b became reduced. Prior stimulation of the cells with phorbol myristate acetate did not increase the rate or extent of cytochrome b reduction in isolated membranes, but did increase both the rate and extent of reduction by NADPH in Triton-treated cells. 3. A cytochrome b was present also in the specific granule fraction of human neutrophils. Its Em (pH 7.0) was found to be -248 mV, very similar to that of the plasma-membrane cytochrome b. 4. The rate of oxidation of reduce cytochrome b-245 by air-saturated buffer, was determined by using stopped-flow techniques. In intact membranes t 1/2 for oxidation was 4.7 ms. This rate is sufficiently rapid to support the view that cytochrome b-245 is the oxidase in the respiratory burst of neutrophils. 5. Plasma-membrane cytochrome b of human neutrophils formed a complex with CO. At room temperature and 1 atm of CO approx. 40% of the cytochrome formed a complex; approx. 60% binding was measured at the increased concentration of dissolved CO achieved at 5 degrees C. The concentration of CO giving 50% binding was 1.18 mM.

scholarly journals Changes in the subcellular distribution of the cytochrome b-245 on stimulation of human neutrophils

1984 ◽  
Vol 219 (1) ◽  
pp. 233-242 ◽  
Author(s):  
R C Garcia ◽  
A W Segal
Keyword(s):  
Plasma Membrane ◽  
Cytochrome B ◽  
Bimodal Distribution ◽  
Human Neutrophils ◽  
Distribution Profile ◽  
Parallel Increase ◽  
Similar Density ◽  
Cytochrome D ◽  
Stimulation Of ◽  
Intracellular Structure

Cytochrome b-245 of neutrophils has a bimodal distribution in sucrose density gradients. The lighter component (d = 1.14) is shown to be associated with the plasma membrane by the similarity between its density and that of markers of this organelle, as well as a parallel increase in the density of the cytochrome and plasma membrane after treatment with digitonin or dimethyl suberimidate. The cytochrome b-245 of monocytes and cytoplasts, the latter produced by the removal of nuclei and granules from neutrophils, was located only in the plasma membrane. The denser peak of cytochrome (d = 1.19), which contained approximately half of the cytochrome b of neutrophils, had a similar density-distribution profile to the specific granules. After hypo-osmotic disruption of this denser material, the cytochrome distributed with the density of membranes, suggesting an original location within the membrane of the intracellular structure. Redistribution of the cytochrome from the granules to the membranes was observed after stimulation of respiratory activity with soluble agents or opsonized particles. This translocation is not responsible for activation of the oxidase system. There was poor agreement between the kinetics of the transfer of cytochromes from the dense component to the membranes, and degranulation of specific-granule contents, suggesting that the cytochrome may be located in another intracellular structure or that its localization becomes further modified after granule fusion.

scholarly journals Subcellular distribution of the Rap1A protein in human neutrophils: colocalization and cotranslocation with cytochrome b559

Blood ◽  
1992 ◽  
Vol 79 (6) ◽  
pp. 1563-1573 ◽  
Author(s):  
MT Quinn ◽  
ML Mullen ◽  
AJ Jesaitis ◽  
JG Linner
Keyword(s):  
Plasma Membrane ◽  
Cytochrome B ◽  
Subcellular Distribution ◽  
Intact Cell ◽  
Human Neutrophils ◽  
Cytochrome B559 ◽  
Thin Sections ◽  
Specific Granule ◽  
Generating System ◽  
Peptide Antibodies

Abstract Rap1A, a low molecular weight guanosine triphosphate-binding protein (LMWG), has been shown previously by us to be associated with purified cytochrome b from stimulated human neutrophils. In the present studies, we show that Rap1A is also associated with affinity-purified cytochrome b from unstimulated neutrophils and use specific anti-Rap1 peptide antibodies to biochemically and immunocytochemically determine the subcellular distribution of Rap1A in resting and activated human neutrophils. Analysis of the subcellular fractionation of unstimulated cells by Western blotting of isopycnic sucrose density gradient fractions with anti-Rap1 peptide antibodies indicated that Rap1A colocalized with cytochrome b in the plasma membrane as well as in the specific granule membranes and that it was translocated, along with cytochrome b, to the plasma membrane when the cells were stimulated with phorbol myristate acetate (PMA). No evidence for a cytosolic localization of Rap1A was found in our studies; however, if the cells were disrupted by sonication, rather than N2 cavitation, a fraction of the Rap1A was released from the membrane. Electron microscopy of thin sections of cryofixed, molecular-distillation dried neutrophils labeled with anti-Rap1 antibody alone or double-labeled with anti-Rap1 and anti- cytochrome b peptide antibodies confirmed our biochemical localization, and quantitation showed that more than half of the specific granule- associated Rap1A was translocated to the plasma membrane in PMA- stimulated cells. Ultrastructural analysis of neutrophils phagocytosing Staphylococcus aureus also demonstrated the translocation of Rap1A with cytochrome b. Approximately 70% of the total Rap1A labeling was associated with the phagolysosomal membrane, the site of assembly of the superoxide-generating system. The colocalization and cotranslocation of Rap1A with cytochrome b in resting and activated neutrophils is consistent with a functional association of these two molecules in the intact cell and provides further evidence for a role of this LMWG in the structure or function of the neutrophil superoxide- generating system.

scholarly journals ADP-ribosylation-factor-regulated phospholipase D activity localizes to secretory vesicles and mobilizes to the plasma membrane following N-formylmethionyl-leucyl-phenylalanine stimulation of human neutrophils

1997 ◽  
Vol 325 (3) ◽  
pp. 581-585 ◽  
Author(s):  
C. P. MORGAN ◽  
H. SENGELOV ◽  
J. WHATMORE ◽  
N. BORREGAARD ◽  
S. COCKCROFT
Keyword(s):  
Plasma Membrane ◽  
Phospholipase D ◽  
Small Gtpases ◽  
Human Neutrophils ◽  
Secretory Vesicles ◽  
Rho Proteins ◽  
Adp Ribosylation ◽  
Activated Neutrophils ◽  
Adp Ribosylation Factor ◽  
Stimulation Of

Phospholipase D (PLD) is responsible for the hydrolysis of phosphatidylcholine to produce phosphatidic acid and choline. Human neutrophils contain PLD activity which is regulated by the small GTPases, ADP-ribosylation factor (ARF) and Rho proteins. In this study we have examined the subcellular localization of the ARF-regulated PLD activity in non-activated neutrophils and cells ‘primed‘ with N-formylmethionyl-leucyl-phenylalanine (fMetLeuPhe). We report that PLD activity is localized at the secretory vesicles in control cells and is mobilized to the plasma membrane upon stimulation with fMetLeuPhe. We conclude that the ARF-regulated PLD activity is translocated to the plasma membrane by secretory vesicles upon stimulation of neutrophils with fMetLeuPhe in inflammatory/priming doses. We propose that this relocalization of PLD is important for the subsequent events occurring during neutrophil activation.

scholarly journals Localization of the 47 kDa phosphoprotein involved in the respiratory-burst NADPH oxidase of phagocytic cells

1989 ◽  
Vol 260 (1) ◽  
pp. 243-248 ◽  
Author(s):  
P G Heyworth ◽  
C F Shrimpton ◽  
A W Segal
Keyword(s):  
Cytochrome B ◽  
Respiratory Burst ◽  
Peptide Mapping ◽  
Granulomatous Disease ◽  
Myristate Acetate ◽  
Phagocytic Cells ◽  
Response Curves ◽  
Respiratory Burst Oxidase ◽  
Cytosolic Factor ◽  
Stimulation Of

A 47 kDa phosphoprotein is involved in the respiratory-burst oxidase of phagocytic cells. After stimulation of neutrophils with phorbol myristate acetate, this phosphoprotein was identified in both the cytosol and membranes. Peptide mapping of the two forms resulted in identical patterns of phosphopeptides. Dose-response curves for accumulation of phosphoprotein in the two sites were very similar, whereas the detection of the phosphoprotein in the cytosol preceded that in the membranes. The membrane-associated 47 kDa phosphoprotein was absent from the neutrophils of patients with X-chromosome-linked chronic granulomatous disease, which lack cytochrome b-245, and intermediate levels were detected in the membranes of their heterozygote carrier mothers. Activation of the neutrophil oxidase system appears to be dependent upon phosphorylation of the cytosolic 47 kDa protein and its association with cytochrome b-245 in the membranes. It is probably the cytosolic factor required for reconstitution of the active oxidase in cell-free systems.

scholarly journals Oxidation-reduction properties of the cytochrome b found in the plasma-membrane fraction of human neutrophils. A possible oxidase in the respiratory burst

1981 ◽  
Vol 194 (2) ◽  
pp. 599-606 ◽  
Author(s):  
A R Cross ◽  
O T Jones ◽  
A M Harper ◽  
A W Segal
Keyword(s):  
Plasma Membrane ◽  
Cytochrome B ◽  
Plasma Membranes ◽  
Mixing Time ◽  
Human Neutrophils ◽  
Half Time ◽  
Sulphur Compounds ◽  
Midpoint Potential ◽  
Oxidation Reduction ◽  
Membrane Bound

The oxidation-reduction midpoint potential of the cytochrome b found in the plasma membrane of human neutrophils has been determined at pH 7.0 (Em,7.0) from measurements of absorption spectra at fixed potentials. In both unstimulated and phorbol myristate acetate-stimulated cells Em,7.0 was -245 mV. Changes in pH affected the Em of the cytochrome b, with a slope of approx. 25 mV/pH unit change. The Em,7.0 of the haem group(s) of the membrane-bound myeloperoxidase of human neutrophils was found to be +34 mV. The plasma membranes contained no detectable ubiquinone, and no iron-sulphur compounds were detected by e.p.r. spectroscopy at 5-20 K. No flavins were detected by e.p.r. spectroscopy. The cytochrome b-245 was not reduced by added NADH or NADPH. Dithionite-reduced cytochrome b-245 formed a complex with CO, supplied as a saturated solution, which was dissociated with 26 microseconds illumination from a xenon flash lamp, and the recombination with CO had a half-time of approx. 6 ms. Partly (80%) reduced cytochrome b-245 was oxidized by added air-saturated buffer with a half-time faster than 1 s at 20 degrees C, a resolution limited by mixing time. These results are compatible with cytochrome b-245 acting as an oxidase.

scholarly journals Subcellular distribution of the Rap1A protein in human neutrophils: colocalization and cotranslocation with cytochrome b559

Blood ◽  
1992 ◽  
Vol 79 (6) ◽  
pp. 1563-1573 ◽  
Author(s):  
MT Quinn ◽  
ML Mullen ◽  
AJ Jesaitis ◽  
JG Linner
Keyword(s):  
Plasma Membrane ◽  
Cytochrome B ◽  
Subcellular Distribution ◽  
Intact Cell ◽  
Human Neutrophils ◽  
Cytochrome B559 ◽  
Thin Sections ◽  
Specific Granule ◽  
Generating System ◽  
Peptide Antibodies

Rap1A, a low molecular weight guanosine triphosphate-binding protein (LMWG), has been shown previously by us to be associated with purified cytochrome b from stimulated human neutrophils. In the present studies, we show that Rap1A is also associated with affinity-purified cytochrome b from unstimulated neutrophils and use specific anti-Rap1 peptide antibodies to biochemically and immunocytochemically determine the subcellular distribution of Rap1A in resting and activated human neutrophils. Analysis of the subcellular fractionation of unstimulated cells by Western blotting of isopycnic sucrose density gradient fractions with anti-Rap1 peptide antibodies indicated that Rap1A colocalized with cytochrome b in the plasma membrane as well as in the specific granule membranes and that it was translocated, along with cytochrome b, to the plasma membrane when the cells were stimulated with phorbol myristate acetate (PMA). No evidence for a cytosolic localization of Rap1A was found in our studies; however, if the cells were disrupted by sonication, rather than N2 cavitation, a fraction of the Rap1A was released from the membrane. Electron microscopy of thin sections of cryofixed, molecular-distillation dried neutrophils labeled with anti-Rap1 antibody alone or double-labeled with anti-Rap1 and anti- cytochrome b peptide antibodies confirmed our biochemical localization, and quantitation showed that more than half of the specific granule- associated Rap1A was translocated to the plasma membrane in PMA- stimulated cells. Ultrastructural analysis of neutrophils phagocytosing Staphylococcus aureus also demonstrated the translocation of Rap1A with cytochrome b. Approximately 70% of the total Rap1A labeling was associated with the phagolysosomal membrane, the site of assembly of the superoxide-generating system. The colocalization and cotranslocation of Rap1A with cytochrome b in resting and activated neutrophils is consistent with a functional association of these two molecules in the intact cell and provides further evidence for a role of this LMWG in the structure or function of the neutrophil superoxide- generating system.

scholarly journals Isolation of plasma membrane from human neutrophils and determination of cytochrome b and quinone content

1981 ◽  
Vol 153 (5) ◽  
pp. 1316-1328 ◽  
Author(s):  
EP Sloan ◽  
DR Crawford ◽  
DL Schneider
Keyword(s):  
Plasma Membrane ◽  
Cytochrome B ◽  
Protein A ◽  
Cell Protein ◽  
Human Neutrophils ◽  
Marker Enzyme ◽  
Whole Cell ◽  
Fold Enrichment ◽  
Dual Localization ◽  
Primary Location

Analyses of plasma membrane and other subcellular fractions indicate that the primary location of cytochrome b in human neutrophils is not the plasma membrane. The procedure developed for the purification of plasma membrane from fresh human neutrophils yielded a 14-fold enrichment in the marker enzyme 5'-nucleotidase and a 10-fold enrichment in ouabain-sensitive ATPase. On sucrose density gradients, the peak density of 5'-nucleotidase activity was 1.12 g/ml, and was shifted after digitonin addition to 1.15 g/ml. Protein in the plasma membrane equalled approximately 8 percent of the whole cell protein. A b-type cytochrome was found to be present in the plasma membrane fraction at a concentration of 205 pmol/mg of protein, which is three times greater than that in the neutrophil overall. Although this cytochrome has been reported previously in the neutrophil, this is the first determination for purified plasma membrane and may indicate that b-type cytochrome has a dual localization in the human neutrophil. Differential centrifugation results suggest that the primary location is in the granules, probably specific granules. Quinone content in the plasma membrane was found to be 740 pmol/mg of protein, a concentration two times greater than in the whole cell. Such a small enhancement of quinone indicates that quinone also is not primarily located in the plasma membrane.

scholarly journals The sarcoplasmic–endoplasmic reticulum Ca2+ ATPase 2b regulates the Ca2+ transients elicited by P2Y2 activation in PC Cl3 thyroid cells

2006 ◽  
Vol 190 (3) ◽  
pp. 641-649 ◽  
Author(s):  
Luca Ulianich ◽  
Maria Giovanna Elia ◽  
Antonella Sonia Treglia ◽  
Antonella Muscella ◽  
Bruno Di Jeso ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Thyroid Cell ◽  
Myristate Acetate ◽  
Thyroid Cells ◽  
Pkc Inhibitor ◽  
Kinase C ◽  
Thyroid Cell Line ◽  
Rat Thyroid ◽  
Stimulation Of

In PC Cl3 cells, a continuous, fully differentiated rat thyroid cell line, P2Y2 purinoceptor activation provoked a transient increase of [Ca2+]i, followed by a decreasing sustained phase. The α and β1 protein kinase C (PKC) inhibitor Gö6976 decreased the rate of decrement to the basal [Ca2+]i level and increased the peak of Ca2+ entry of the P2Y2-provoked Ca2+transients. These effects of Gö 6976 were not caused by an increased permeability of the plasma membrane, since the Mn2+ and Ba2+ uptake were not changed by Gö 6976. Similarly, the Na+/Ca2+ exchanger was not implicated, since the rate of decrement to the basal [Ca2+]i level was equally decreased in physiological and Na+-free buffers, in the presence of Gö 6976. On the contrary, the activity of the sarcoplasmic–endoplasmic reticulum Ca2+ATPase (SERCA) 2b was profoundly affected by Gö 6976 since the drug was able to completely inhibit the stimulation of the SERCA 2b activity elicited by P2-purinergic agonists. Finally, the PKC activator phorbol myristate acetate had effects opposite to Gö 6976, in that it markedly increased the rate of decrement to the basal [Ca2+]i level after P2Y2 stimulation and also increased the activity of SERCA 2b. These results suggest that SERCA 2b plays a role in regulating the sustained phase of Ca2+ transients caused by P2Y2 stimulation.

The Kinetics of Oxidation of Cytochrome B are in Agreement with the Q-Cycle Hypothesis

1987 ◽  
pp. 517-522 ◽  
Author(s):  
S. de Vries ◽  
A. N. van Hoek ◽  
A. ten Bookum ◽  
J. A. Berden
Keyword(s):  
Cytochrome B ◽  
Kinetics Of Oxidation ◽  
Q Cycle ◽  
Kinetics Of
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