Disease relevance of NCF4

• A novel cytosolic component, p40phox, of respiratory burst oxidase associates with p67phox and is absent in patients with chronic granulomatous disease who lack p67phox [1].
• Concentrations of plasma histamine and serum neutrophil chemotactic factor (NCF) were measured in seven atopic asthmatics who developed exercise-induced asthma (EIA) after a treadmill task [2].
• Using human airway epithelial cells grown in primary culture, we examined in vitro activation of NF-kappaB in cells isolated from five CF (DeltaF508/DeltaF508) and three non-CF (NCF) patients in response to Pseudomonas aeruginosa [3].
• Alveolar macrophages from subjects with asbestosis released more NCF (97 +/- 19 neutrophils per high-power field [N/HPF]) than controls (3 +/- 1 N/HPF; p less than 0.01) [4].
• The correlation between lipid metabolism and rate of growth was studied in human normal conjunctival (NCF) and primary pterygium fibroblasts (PFs) in primary culture [5].

High impact information on NCF4

• The antibody against the COOH terminus of p67phox was able to communoprecipitate p40phox in conjunction with p67phox itself as was expected [6].
• Involvement of p40phox in activation of phagocyte NADPH oxidase through association of its carboxyl-terminal, but not its amino-terminal, with p67phox [6].
• 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 [6].
• 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 [6].
• A heat-stable neutrophil chemotactic factor (NCF) has been identified in the serum of 13 atopic asthmatic subjects after treadmill exercise [7].

Chemical compound and disease context of NCF4

• Biochemical analysis demonstrated that several kinds of NCF, including those derived from the complement component C5 and alveolar macrophages, were present in the BAL fluid from patients with CAD and respiratory infections [8].

Biological context of NCF4

• Ku70, a regulatory component of the DNA-dependent protein kinase, was identified by a yeast two-hybrid screen of a B lymphocyte cDNA library as a partner of p40phox, a regulatory component of the O2--producing NADPH oxidase [9].
• Among plasmids from positive clones, a plasmid contained an insert which has homology with human p40phox, a cytosolic component of phagocyte oxidase [10].
• We hypothesize that Rac-GTP binds the p67phox N-terminal domain encompassing amino acids 170-199 that transmits a conformational change which causes p40phox to dissociate from its binding site in the p67phox C-terminus [11].
• The other components of the respiratory-burst oxidase are water-soluble proteins of cytosolic origin, namely p67phox, p47phox, p40phox and Rac [12].
• This suggests that, in the cell, the phosphorylation of p40phox and of p47phox are under the control of two different kinase pathways [13].

Anatomical context of NCF4

• The Ku70 autoantigen interacts with p40phox in B lymphocytes [9].
• Moreover, we report that Ku70 and p40phox colocalize in B lymphocytes and in transfected Cos-7 cells [9].
• We also show that in neutrophils from a patient lacking p67phox, the amount of cytosolic p40phox was decreased by about 40% [14].
• Western blot analysis showed that both cell lines expressed the phagocyte oxidase (phox) cytosolic proteins Rac1, p40phox, and p67phox [15].
• The 40-kDa component of the phagocyte NADPH oxidase (p40phox) is phosphorylated during activation in differentiated HL60 cells [13].

Associations of NCF4 with chemical compounds

• Chronic ACT was associated with a variant of the NAD(P)H oxidase subunit NCF4 (rs1883112, -212A-->G; symbols with right-pointing arrows, as edited?' odds ratio [OR], 2.5; 95% CI, 1.3 to 5.0) [16].
• The entire coding region of p40phox was shown to interact with TRX both in assays of histidine prototrophy and beta-galactosidase activity; in contrast, no interaction was observed with substituted mutant TRX (C32S/C35S), which lacks reducing activity [10].
• Although actin has been reported to be involved in O2- generation, the p40phox profile did not correspond to that of actin [1].
• The tight association between p40phox and p67phox was not affected by treatment with a mixture of deoxycholate and Nonidet P-40, until subjected to SDS-PAGE [1].
• Genomic structure, chromosomal localization, start of transcription, and tissue expression of the human p40-phox, a new component of the nicotinamide adenine dinucleotide phosphate-oxidase complex [17].

Physical interactions of NCF4

• These results showed that p40phox interacts with TRX and indicated the possibility of TRX-dependent regulation of phagocyte oxidase activity [10].
• Binding studies revealed that coronin attaches to the C-terminal half of p40phox, a binding partner of p67phox [18].
• CONCLUSIONS: In the resting cell, the Pro-rich motif of p47phox interacts with the SH3 domain of p40phox, which in turn associates with p67phox [19].

Enzymatic interactions of NCF4

• When 32P-labeled guinea pig neutrophils were stimulated by phorbol 12-myristate 13-acetate, p40-phox was phosphorylated as p47-phox [20].

Other interactions of NCF4

• Demonstration of the interaction of thioredoxin with p40phox, a phagocyte oxidase component, using a yeast two-hybrid system [10].
• Furthermore, we show that its N-terminal part binds to the PX domain of p47phox and p40phox [21].
• Truncated constructs of p40phox and Ku70 were used to map the interacting sites [9].
• Further, the analyzed part of the C. intestinalis genome and EST database do not seem to present p40phox and Nox5 [22].
• To characterize these mRNAs, we performed reverse transcription using total RNA from HL-60 cells, and amplified the coding region of p40phox by polymerase chain reaction with oligonucleotide primers [23].

Analytical, diagnostic and therapeutic context of NCF4

• In this report we describe a novel cytosolic component, p40phox, which consistently behaves with p67phox through immunoprecipitation and column works, and is missing in patients with CGD who lack p67phox [1].
• In addition to identifying the mRNA transcript on Northern blot analysis in cells known to express components of the NADPH-oxidase, polymorphonuclear leukocytes, monocytes, B lymphoblastoid cell lines, and eosinophils, p40-phox is also expressed in two other cell types of white cell lineage, mast cells, and basophils [17].
• Based on fluorescent in situ hybridization (FISH) studies and analysis of somatic hybrid cell lines, the chromosomal location of p40-phox is human chromosome 22q13 [17].
• Using immunofluorescence confocal microscopy, we found that p40phox colocalized with filamentous actin [24].
• Intensive site-directed mutagenesis to the motif in p40phox revealed that it plays a critical role in the binding to p67phox [25].

References