Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.3.1 (alkaline phosphatase)
47,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Glycosyl-phosphatidylinositol (GPI) anchored membrane proteins have been reported to be deficient on affected paroxysmal nocturnal haemoglobinuria (PNH) blood cells. In the present study we investigated the deficiency of several GPI anchored membrane proteins on PNH neutrophils (PMN) and monocytes from 10 patients with PNH. Decay-accelerating factor (DAF) and Fc gamma R-III (CD16) on PMN, DAF and CD14 on monocytes, were investigated by two-colour immunofluorocytometry. Neutrophil alkaline phosphatase activity was also assayed on PNH neutrophils. Normal human PMN were always shown phenotypically to be DAF+/CD16+. A DAF-/CD16- subpopulation of PMN was demonstrated in all the patients studied. In six out of the 10 patients, deficiencies of DAF and CD16 were found simultaneously on affected PNH PMN. The percentage of DAF- PMN showed a positive correlation with the neutrophil alkaline phosphatase (NAP) score. However, it should be noted that, in four out of the 10 patients with PNH, a DAF+/CD16- subpopulation of PMN was also clearly found. This may indicate that the deficiencies of DAF and CD16 on PNH PMN are heterogeneous. Normal human monocytes were demonstrated to be DAF+/CD14+, whereas PNH monocytes consisted of subpopulations of DAF+/CD14+ and DAF-/CD14-. In the same patients with PNH, the deficiencies of DAF on PMN and monocytes correlated well with each other. These results suggest that, at least in some patients with PNH, the mechanisms which induce the membrane defects of PNH blood cells are heterogeneous.
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PMID:Deficiency of glycosyl-phosphatidylinositol anchored proteins on paroxysmal nocturnal haemoglobinuria (PNH) neutrophils and monocytes: heterogeneous deficiency of decay-accelerating factor (DAF) and CD16 on PNH neutrophils. 170 8

Anti-Fc gamma R IgM monoclonal antibodies (mAbs) isolated from lipopolysaccharide-stimulated spleen cells from tightskin (TSK) mice were found to be polyspecific, reacting with a wide variety of molecules, including double-stranded DNA, topoisomerase, RNA polymerase, and different collagen types. Approximately 60% of the polyspecific IgM mAbs have anti-Fc gamma R specificity. These anti-Fc gamma R mAbs induce the release of hydrolases from both azurophil and specific granules of human neutrophils. 25-45% of the total cellular content (determined in Nonidet P-40 lysates) of neutrophil elastase, 10-25% of beta-glucuronidase, and 30-50% of alkaline phosphatase was released after incubation with the mAbs. The degranulation process was accompanied by dramatic morphological changes shown by scanning and transmission electron microscopy. The release of hydrolytic enzymes stimulated by the IgM anti-Fc gamma R mAbs was inhibited by preincubation of neutrophils with Fab fragments of either anti-human Fc gamma RII (IV.3) or anti-human Fc gamma RIII (3G8) mAbs. The binding of the anti-Fc gamma R TSK mAbs to human neutrophils was inhibited by Fab fragments of mAb 3G8. However, we found that the TSK anti-Fc gamma R mAbs do not bind to human Fc gamma RII expressed in either CHO cells or the P388D1 mouse macrophage cell line. Since the enzyme release could be inhibited by Fab fragments of mAb IV.3, we suggest that the signal transduction may require Fc gamma RII activation subsequent to crosslinking of the glycan phosphatidyl inositol-anchored Fc gamma RIII-1. These data demonstrate for the first time that polyspecific autoantibodies with Fc gamma R specificity can trigger neutrophil enzyme release via human Fc gamma RIII-1 in vitro and indicate a possible role for such autoantibodies in autoimmune inflammatory processes.
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PMID:IgM anti-Fc gamma R autoantibodies trigger neutrophil degranulation. 182 27

In four healthy volunteers, we analyzed in detail the immediate in vivo effects on circulating neutrophils of subcutaneous administration of 300 micrograms of granulocyte colony-stimulating factor (G-CSF). Neutrophil activation was assessed by measurement of degranulation. Mobilization of secretory vesicles was shown by a decrease in leukocyte alkaline phosphatase content of the circulating neutrophils. Furthermore, shortly postinjection, Fc gamma RIII was found to be upregulated from an intracellular pool that we identified by immunoelectron microscopy as secretory vesicles. Intravascular release of specific granules was shown by increased plasma levels of lactoferrin and by upregulation of the expression of CD66b and CD11b on circulating neutrophils. Moreover, measurement of fourfold elevated plasma levels of elastase, bound to its physiologic inhibitor alpha 1-antitrypsin, indicated mobilization of azurophil granules. However, no expression of CD63, a marker of azurophil granules, was observed on circulating neutrophils. G-CSF--induced mobilization of secretory vesicles and specific granules could be mimicked in whole blood cultures in vitro, in contrast to release of azurophil granules. Therefore, we postulate that the most activated neutrophils leave the circulation, as observed shortly postinjection, and undergo subsequent stimulation in the endothelial microenvironment, resulting in mobilization of azurophil granules. Our data demonstrate that G-CSF should be regarded as a potent immediate activator of neutrophils in vivo.
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PMID:Granulocyte colony-stimulating factor administration to healthy volunteers: analysis of the immediate activating effects on circulating neutrophils. 752 51

CD14 is a glycosylphosphatidylinositol (GPI)-anchored protein on the surfaces of monocytes and polymorphonuclear leukocytes (PMN) that binds and initiates cellular responses to bacterial LPS. PMN also contain an intracellular pool of CD14 that can be deployed rapidly to the cell surface in response to stimulation with a variety of agonists. To determine which of the well-characterized subcellular compartments of PMN contains CD14, cells were cavitated and fractionated on Percoll gradients. The gradient fractions were assayed for CD14 by ELISA and Western blot and for the marker proteins beta-glucuronidase (azurophil granules), vitamin B12 binding protein (specific granules), alkaline phosphatase (secretory vesicles and plasma membrane), and HLA (plasma membrane). Approximately one-half of the CD14 ran with plasma membrane fractions and one-half with intracellular membranes of light density. Both intracellular and cell surface CD14 were associated tightly with membrane, and both forms showed identical electrophoretic mobility. The intracellular CD14 was clearly not present in azurophil granules or specific granules, but ran precisely with alkaline phosphatase, a marker for secretory vesicles. Parallel studies showed that an additional GPI-linked protein, Fc gamma RIII (CD16), also fractionated precisely with CD14 and alkaline phosphatase. Association of CD14 with secretory vesicles were confirmed by studies on cells stimulated with the formyl peptide fNLLP for 20 min at 37 degrees C before fractionation. This treatment caused translocation of CD14 from intracellular fractions to plasma membrane fractions. No release of the specific granule marker vitamin B12 binding protein was observed under these conditions, whereas two other GPI-anchored proteins, alkaline phosphatase and CD16, moved coincidentally with CD14 to comigrate with the plasma membrane. Time course studies of CD14 and CD16 surface expression confirmed the rapid and coordinate up-regulation of these proteins. Thus, the intracellular compartment containing CD14 and CD16 had the properties of secretory vesicles. These vesicles may represent a specialized membrane domain of PMN enriched in GPI-anchored proteins.
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PMID:Endotoxin receptors (CD14) are found with CD16 (Fc gamma RIII) in an intracellular compartment of neutrophils that contains alkaline phosphatase. 754 38

A nonradioactive method was employed to detect different cell membrane antigens on human polymorphonuclear granulocytes, monocytes and platelets. We compared the reactivity of one monoclonal antibody, N1III10, assumed to be Fc gamma RII-specific by functional assays, with other well-characterized monoclonal antibodies and human sera. Intact cells were incubated with biotin N-hydroxysulfosuccinimide ester which preferentially reacts with lysine residues in polypeptides. Biotin-labeled cells were lysed and the antigen was isolated from the cell lysate by immunoprecipitation with the antibody bound to Protein A-Sepharose. The precipitates were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, transferred onto nitrocellulose membrane, and visualized by a streptavidin-alkaline phosphatase system with a suitable substrate. Using this biotin-labeling system we could show that N1III10 detects a 40 kDa antigen on monocytes and platelets, comparable to that expected of Fc gamma RII monoclonal antibodies.
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PMID:Biotinylation: a nonradioactive method for the identification of cell surface antigens in immunoprecipitates. 758 58

We performed a detailed kinetic study on the in vivo effect of a single subcutaneous dose of granulocyte colony-stimulating factor (G-CSF; 300 micrograms) in four healthy individuals on the expression and function of neutrophil Fc gamma receptors (Fc gamma R). G-CSF did not induce Fc gamma RI (CD64) on circulating neutrophils. However, neutrophils newly formed in response to G-CSF were Fc gamma RI positive and were able to perform antibody-dependent cellular cytotoxicity in an Fc gamma RI-dependent way. Fc gamma RII (CD32) expression was not changed significantly. Fc gamma RIII (CD16, phosphatidylinositol-linked) expression, slightly increased immediately (30 minutes) postinjection, was found to be strongly decreased on the newly formed population. For comparison, we studied the expression of the PI-linked proteins leukocyte alkaline phosphatase (LAP) and CD14. Intracellular levels of LAP mirrored the biphasic expression pattern as membrane-bound Fc gamma RIII. In contrast, CD14 expression on neutrophils was initially constant, followed by high levels on the newly formed neutrophils. Soluble CD14 levels were found to be elevated transiently, whereas peak levels of soluble Fc gamma III were observed as late as 6 days postinjection. In conclusion, we have shown that G-CSF results in an immunophenotypically and functionally altered neutrophil population for an important part as a result of its effect on myeloid precursor cells.
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PMID:Recombinant granulocyte colony-stimulating factor administration to healthy volunteers: induction of immunophenotypically and functionally altered neutrophils via an effect on myeloid progenitor cells. 769 76

We have developed a highly sensitive and quantitative, non-isotopic method of in situ hybridization in which the level of probe binding to intracellular mRNA is determined using an ELISA based detection method. Highly purified cell preparations or cells from a cultured cell line are centrifuged into 96 well microtiter plates. The cells are fixed with formalin and pre-treated with Triton X-100 and Nonidet P40 before photobiotin labeled cDNA probes are applied. The biotin from the hybridization is detected using multiple applications of streptavidin and biotinylated alkaline phosphatase and then visualized by the p-NPP (p-nitrophenyl phosphate) conversion method. We have determined a number of the optimal parameters in the procedure including the effects of cell numbers per well, development times and standardization of data using ubiquitous beta-actin mRNA and poly-A+ RNA expression as controls. We have used the technique to study the level of expression of FcgR mRNA in platelets and precursors. We found that platelets and megakaryoblastic cell lines only express mRNA for Fc gamma RII. The presence of the Fc gamma RII molecules was confirmed by complementary studies using immunohistochemistry with specific monoclonal antibodies IV.3 and KB61.
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PMID:Quantitation of Fc gamma RII mRNA in platelets and megakaryoblastic cell lines by a new method of in situ hybridization. 820 59

The ability of the phosphatidylinositol-specific phospholipase C (PI-PLC) from Listeria monocytogenes to hydrolyze glycosyl phosphatidylinositol (GPI)-anchored membrane proteins was compared with the ability of the PI-PLC from Bacillus thuringiensis to hydrolyze such proteins. The L. monocytogenes enzyme produced no detectable release of acetylcholinesterase from bovine, sheep, and human erythrocytes. The cleavage of the GPI anchors of alkaline phosphatase from rat and rabbit kidney slices was less than 10% of the cleavage seen with the PI-PLC from B. thuringiensis. Activity for release of Fc gamma receptor IIIB (CD16) on human granulocytes was also low. Variations in pH and salt concentration had little effect on the release of GPI-anchored proteins. Our data show that L. monocytogenes PI-PLC has low activity on GPI-anchored proteins.
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PMID:Listeria monocytogenes phosphatidylinositol (PI)-specific phospholipase C has low activity on glycosyl-PI-anchored proteins. 825 89

Polyspecific and organ specific autoimmune diseases are often accompanied by prolonged clearance of immune complexes. In mice, impaired macrophage Fc gamma receptor function may be associated with autoantibody against Fc gamma receptors. To extend these observations to autoimmune human disease, we transformed with EBV peripheral lymphocytes from a patient with terminal progressive systemic sclerosis and screened for clones secreting anti-Fc gamma receptor Ig. A clone, N55, which secretes a high affinity anti-Fc gamma receptor IgG2 antibody was obtained. The Fab fragment of N55 bound to human neutrophils, NK cells, but not to monocytes, consistent with specificity for Fc gamma RIII (CD16). N55 Fab competed weakly for the binding of anti-Fc gamma RIII mAb 3G8 to neutrophils but did not have any effect on staining with the anti-Fc gamma RII mAb, IV.3. N55 Fab did not bind to peripheral monocytes, but did bind to monocytes incubated with TGF-beta (24 h) to induce Fc gamma RIII. The specificity of N55 IgG for Fc gamma RIII was confirmed by ELISA using secreted recombinant Fc gamma RIIA and Fc gamma RIIIB protein to coat microtiter wells. N55 IgG triggered the release from neutrophils of beta-glucuronidase, arylsulfatase and alkaline phosphatase. Such antibody may play a pathogenic role in progressive systemic sclerosis.
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PMID:An Fc gamma RIII (CD16)-specific autoantibody from a patient with progressive systemic sclerosis. 838 99

Chronic myeloid leukemic (CML) granulocytes exhibit defects in several functions, some of which have been associated with changes in the expression of cell surface molecules, actin reorganization and lowered levels of total cellular actin. In this study, we show by northern blotting that the steady-state level of mRNA for actin is not decreased in the CML granulocyte. Our data suggest that the lowered levels of actin protein in the leukemic granulocyte may be due to altered control at the translational/post-translational step, rather than at the level of transcription/post-transcription, implicated in the regulation of expression of the surface molecules, Fc gamma RII, Fc gamma RIII and alkaline phosphatase.
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PMID:Actin mRNA is not lowered in chronic myeloid leukemic granulocytes. 894 83


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