Phagocytes such as neutrophils play a vital role in host defense against microbial pathogens. The anti-microbial function of neutrophils is based on the production of superoxide anion (O2(.-)), which generates other microbicidal reactive oxygen species (ROS) and release of antimicrobial peptides and proteins. The enzyme responsible for O2(.-) production is called the NADPH oxidase or respiratory burst oxidase. This multicomponent enzyme system is composed of two transmembrane proteins (p22phox and gp91phox, also called NOX2, which together form the cytochrome b(558)) and four cytosolic proteins (p47phox, p67phox, p40phox and a GTPase Rac1 or Rac2), which assemble at membrane sites upon cell activation. NADPH oxidase activation in phagocytes can be induced by a large number of soluble and particulate agents. This process is dependent on the phosphorylation of the cytosolic protein p47phox. p47phox is a 390 amino acids protein with several functional domains: one phox homology (PX) domain, two src homology 3 (SH3) domains, an auto-inhibitory region (AIR), a proline rich domain (PRR) and has several phosphorylated sites located between Ser303 and Ser379. In this review, we will describe the structure of p47phox, its phosphorylation and discuss how these events regulate NADPH oxidase activation.
*Disease ; Enzyme Activation ; Humans ; Membrane Glycoproteins/chemistry/*metabolism ; NADPH Oxidase/chemistry/genetics/*metabolism ; Phagocytes/cytology/*metabolism ; Phosphorylation ; Protein Conformation

Changes in microparticles (MP) from red blood cell (RBC) concentrates in the context of irradiation have not been investigated. The aim of this study was to evaluate how irradiation affects the number of MPs within transfusion components. Twenty RBC concentrates, within 14 days after donation, were exposed to gamma rays (dose rate: 25 cGy) from a cesium-137 irradiator. Flow cytometry was used to determine the numbers of MPs derived from RBC concentrates before and 24 hr after irradiation. The mean number of MPs (±standard deviation) in RBC concentrates was 21.9×10(9)/L (±22.7×10(9)/L), and the total number of MPs ranged from 2.6×10(9)/L to 96.9×10(9)/L. The mean number of MPs increased to 22.6×10(9)/L (±31.6×10(9)/L) after irradiation. Before irradiation, the CD41-positive and CD235a-positive MPs constituted 9.5% (1.0×10(9)/L) and 2.2% (263×10(6)/L) of total MPs, respectively. After irradiation, CD41-positive MPs increased to 12.1% (1.5×10(9)/L) (P=0.014), but the CD235a-positive MPs decreased to 2.0% (214×10(6)/L) of the total MPs (P=0.369). Irradiation increases the number of CD41-positive MPs within RBC concentrates, suggesting the irradiation of RBC concentrates could be associated with thrombotic risk of circulating blood through the numerical change.
Cell-Derived Microparticles/chemistry/*metabolism/radiation effects ; Erythrocytes/*cytology/radiation effects ; Flow Cytometry ; Gamma Rays ; Humans ; Membrane Glycoproteins/metabolism ; Metalloendopeptidases/metabolism ; Platelet Membrane Glycoprotein IIb/metabolism

BACKGROUNDThe side effects of cyclosporine therapy include thromboembolic complications. However, the mechanisms underlying the hypercoagulable state induced by cyclosporine are not fully understood. Cyclosporine binds to red blood cells (RBCs) with a high affinity in circulation and alters the membranes of RBCs. Therefore, we propose that such alterations in RBCs membranes play a role in cyclosporine-induced coagulopathy and this disorder may be rectified by lactadherin, a phosphatidylserine binding protein.

METHODSRBCs from healthy adults were treated with various concentrations of cyclosporine. Procoagulant activity of the RBC membrane was measured by the single stage recalcification time and confirmed by detection of tenase and thrombin assembly through enzymatic assays. Inhibition assays of coagulation were carried out in the presence of lactadherin, annexin V or antitissue factor. Phosphatidylserine exposure was detected by flow cytometry and confocal microscopy through binding with fluorescein isothiocyanate (FITC)-labeled lactadherin as well as FITC annexin V.

RESULTSRBCs treated with cyclosporine demonstrated increased procoagulant activity. Cyclosporine treatment markedly shortened the clotting time of RBCs ((305 +/- 10) seconds vs (366 +/- 15) seconds) and increased the generation of intrinsic factor Xase ((7.68 +/- 0.99) nmol/L vs (2.86 +/- 0.11) nmol/L) and thrombin ((15.83 +/- 1.37) nmol/L vs (4.88 +/- 0.13) nmol/L). Flow cytometry and confocal microscopy indicated that cyclosporine treatment induced an increased expression of phosphatidylserine on the RBC membrane. Lactadherin was more sensitive in detecting phosphatidylserine exposure of the RBC membrane than annexin V. The modulating effect of procoagulant activity was concomitant with and dependent on phosphatidylserine exposure. Blocking of phosphatidylserine with lactadherin effectively inhibited over 90% of FXa generation and prothrombinase activity and prolonged coagulation time.

CONCLUSIONSProcoagulant properties of RBCs membranes resulting from phosphatidylserine exposure may play an important role in cyclosporine-induced thrombosis. Lactadherin can be used as a sensitive probe for phosphatidylserine detection. Its high affinity for phosphatidylserine may provide a new approach for the treatment of cyclosporine induced thrombogenic properties.

Adult ; Animals ; Annexin A5 ; chemistry ; Cattle ; Cell Membrane ; drug effects ; metabolism ; Cells, Cultured ; Cyclosporine ; pharmacology ; Erythrocytes ; drug effects ; metabolism ; Flow Cytometry ; Humans ; Membrane Glycoproteins ; chemistry ; Microscopy, Confocal ; Milk Proteins ; chemistry ; Phosphatidylserines ; chemistry ; metabolism ; Thrombosis ; chemically induced ; metabolism

OBJECTIVETo investigate the distribution, changes and a possible role for retinal dopamine transporter (DAT) in experimental myopia in chickens.

METHODSTwo-day-old chickens were divided into four groups. Chicken eyes were fitted with lenses of -10D,-20D and translucent goggles unilaterally. Normal eyes were used as controls. After 3 wk, all chickens were given an intramuscular injection of (125)I-beta-CIT 2beta-carbomethoxy-3beta-(4-iodophenyl)tropane and sacrificed two hours post injection. Retinal pigment epithelium (RPE) and the neural retina were obtained together or RPE was dissected out from the neural retina. Radioactive DAT from each specimen was assayed by gamma-counter.

RESULTSRetinal DAT was detected in RPE specimens rather than in the neural retina in all eyes. Radioactive DAT in myopic eyes was higher, compared with control eyes.

CONCLUSIONSRetinal DAT is mainly located in the RPE and may be involved in the formation of lens induced myopia (LIM) and form deprivation myopia (FDM). These methods may provide a new approach for further studying the role of the dopamine system in experimental myopia.

Animals ; Chickens ; Dopamine Plasma Membrane Transport Proteins ; Eye ; growth & development ; Membrane Glycoproteins ; Membrane Transport Proteins ; analysis ; physiology ; Myopia ; metabolism ; Nerve Tissue Proteins ; Retina ; chemistry

Leukocyte immunoglobulin-like receptors (LILRs), also called CD85s, ILTs, or LIRs, are important mediators of immune activation and tolerance that contain tandem immunoglobulin (Ig)-like folds. There are 11 (in addition to two pseudogenes) LILRs in total, two with two Ig-like domains (D1D2) and the remaining nine with four Ig-like domains (D1D2D3D4). Thus far, the structural features of the D1D2 domains of LILR proteins are well defined, but no structures for the D3D4 domains have been reported. This is a very important field to be studied as it relates to the unknown functions of the D3D4 domains, as well as their relative orientation to the D1D2 domains on the cell surface. Here, we report the crystal structures of the D3D4 domains of both LILRB1 and LILRB2. The two Ig-like domains of both LILRB1-D3D4 and LILRB2-D3D4 are arranged at an acute angle (∼60°) to form a bent structure, resembling the structures of natural killer inhibitory receptors. Based on these two D3D4 domain structures and previously reported D1D2/HLA I complex structures, two alternative models of full-length (four Ig-like domains) LILR molecules bound to HLA I are proposed.
Amino Acid Sequence ; Antigens, CD ; chemistry ; Crystallography, X-Ray ; Histocompatibility Antigens Class I ; chemistry ; Humans ; Immunoglobulins ; chemistry ; Leukocyte Immunoglobulin-like Receptor B1 ; Membrane Glycoproteins ; chemistry ; Models, Molecular ; Peptides ; chemistry ; metabolism ; Protein Binding ; Protein Structure, Tertiary ; Receptors, Immunologic ; chemistry ; Signal Transduction

OBJECTIVETo construct the yeast two-hybrid system, and screen the proteins which interact with FasL, and investigate the relationship of FasL and hepatic metastasis of colorectal carcinoma.

METHODSWe have cloned the FasL gene into the pGBKT7 vector as the bait, then screened the fetal liver cDNA library, and have got a series of specific proteins that interact with FasL protein. Using the bioinformatics, we analyzed the interacting proteins in the mechanism of hepatic metastasis of colorectal carcinoma.

RESULTSWe have screened several proteins that interaction with FasL protein, including metallothionein 1K, 1G, 2A, cathepsin B, fatty acid synthase, interferon alpha-inducible protein 27, phospholipid scramblase, Ser/Thr-like kinase, anchor attachment protein, fibulin-5.

CONCLUSIONSWe have successfully constructed the yeast two-hybrid system, and preliminary identified that the interaction between FasL, metallothionein, cathepsin and anchor attachment protein is radically related to the hepatic metastasis of colorectal carcinoma.

Cathepsin B ; metabolism ; Cloning, Molecular ; Colorectal Neoplasms ; chemistry ; pathology ; Fas Ligand Protein ; Gene Library ; Humans ; In Vitro Techniques ; Liver Neoplasms ; chemistry ; secondary ; Membrane Glycoproteins ; genetics ; metabolism ; Metallothionein ; metabolism ; Protein Binding ; Tumor Necrosis Factors ; genetics ; metabolism ; Two-Hybrid System Techniques ; Yeasts ; genetics

OBJECTIVETo evaluate the relationship between levels of soluble Fas (sFas) and soluble Fas ligand (sFasL) in serum and peritoneal fluid of endometriosis-associated infertility.

METHODSThe soluble Fas ligand and soluble Fas levels in serum and peritoneal fluid of 20 infertile patients with endometriosis were assessed with enzyme-linked immunosorbent assay, and were compared with 14 infertile patients due to chronic pelvic infectious disease and 16 fertile controls.

RESULTSThe sFasL levels were significantly higher in infertile patients with endometriosis (175.09 +/- 80.55 pg/mL in serum and 284.50 +/- 152.38 pg/mL in peritoneal fluid) than those of infertile controls (88.47 +/- 43.55 pg/mL in serum and 17.30 +/- 9.62 pg/mL in peritoneal fluid) and fertile controls (16.13 +/- 11.75 pg/mL in serum and 8.84 +/- 2.31 pg/mL in peritoneal fluid). In contrast, as for the sFas levels, infertile patients with endometriosis (828.60 +/- 429.65 pg/mL in serum and 349.61 +/- 288.89 pg/mL in peritoneal fluid) did not show any significant difference compared with those in infertile patients resulting from pelvic infectious disease (868.75 +/- 570.48 pg/mL in serum and 181.76 +/- 157.78 pg/mL in peritoneal fluid) and fertile control (822.26 +/- 129.12 pg/mL in serum and 318.42 +/- 145.16 pg/mL in peritoneal fluid).

CONCLUSIONSBased upon these results, high level of sFasL in serum and peritoneal fluid and thus apoptosis mediated by it may be implicated in the mechanism involved in endometriosis-related infertility.

Ascitic Fluid ; chemistry ; Endometriosis ; complications ; metabolism ; Fas Ligand Protein ; Female ; Humans ; Infertility, Female ; etiology ; metabolism ; Ligands ; Membrane Glycoproteins ; blood ; metabolism ; Pelvic Infection ; complications ; metabolism ; Solubility ; fas Receptor ; blood ; metabolism

Lipopolysaccharide (LPS) is the major constituents of the outer membrane of Gram-negative bacteria. LPS recognition and signal transmission are key events in the host defense reaction towards Gram-negative bacteria and are associated with many disorders. Multiple signaling pathways are involved in the response to LPS. With the help of LPS-binding protein and CD14, TLR4 binds with LPS, then recruits myeloid differentiation factor 88 and IL-1 receptor-associated kinase, and further phosphorylates and activates TNF receptor associated factor 6 (TRAF6). The activated TRAF6 leads to the activation of transcription factor NF-kappaB and MAP kinase's pathways that involves in LPS-induced cellular responses and the production of proinflammatory cytokines such as TNF-alpha, IL-6 and IL8.
Acute-Phase Proteins ; metabolism ; Carrier Proteins ; metabolism ; Gram-Negative Bacteria ; chemistry ; Lipopolysaccharide Receptors ; metabolism ; Lipopolysaccharides ; pharmacology ; Membrane Glycoproteins ; metabolism ; Mitogen-Activated Protein Kinase Kinases ; metabolism ; NF-kappa B ; physiology ; Signal Transduction

Chronic granulomatous disease (CGD) is a rare genetic disease, which is caused by defects in the NADPH oxidase complex (gp91phox, p22phox, p40phox, p47phox, and p67phox) of phagocytes. This defect results in impaired production of superoxide anions and other reactive oxygen species (ROS), which are necessary for killing bacterial and fungal microorganisms and leads to recurrent, life-threatening bacterial and fungal infections and granulomatous inflammation. The dihydrorhodamine (DHR) flow cytometry assay is a useful diagnostic tool for CGD that can detect absent or reduced NADPH oxidase activity in stimulated phagocytes. We report a patient with X-linked CGD carrying a novel mutation of the CYBB gene whose chimerism status following hematopoietic stem cell transplantation (HSCT) has been rapidly determined using the DHR assay. The level of DHR activity correlates well with short tandem repeat PCR analysis. Considering the advantages of this simple, rapid, and cost-effective procedure, serial measurement of DHR assay would facilitate the rapid determination of a patient's engraftment status, as a supplementary monitoring tool of chimerism status following HSCT.
Base Sequence ; *Chimerism ; DNA Mutational Analysis ; Flow Cytometry ; Granulomatous Disease, Chronic/*diagnosis/*enzymology/genetics/surgery ; *Hematopoietic Stem Cell Transplantation ; Homozygote ; Humans ; Infant, Newborn ; Male ; Membrane Glycoproteins/chemistry/*genetics ; Mutation ; NADPH Oxidase/chemistry/*genetics ; Polymerase Chain Reaction ; Rhodamines/chemistry/metabolism

Uch37 is a de-ubiquitinating enzyme that is activated by Rpn13 and involved in the proteasomal degradation of proteins. The full-length Uch37 was shown to exhibit low iso-peptidase activity and is thought to be auto-inhibited. Structural comparisons revealed that within a homo-dimer of Uch37, each of the catalytic domains was blocking the other's ubiquitin (Ub)-binding site. This blockage likely prevented Ub from entering the active site of Uch37 and might form the basis of auto-inhibition. To understand the mode of auto-inhibition clearly and shed light on the activation mechanism of Uch37 by Rpn13, we investigated the Uch37-Rpn13 complex using a combination of mutagenesis, biochemical, NMR, and small-angle X-ray scattering (SAXS) techniques. Our results also proved that Uch37 oligomerized in solution and had very low activity against the fluorogenic substrate ubiquitin-7-amino-4-methylcoumarin (Ub-AMC) of de-ubiquitinating enzymes. Uch37Δ(Hb,Hc,KEKE), a truncation removal of the C-terminal extension region (residues 256-329) converted oligomeric Uch37 into a monomeric form that exhibited iso-peptidase activity comparable to that of a truncation-containing the Uch37 catalytic domain only. We also demonstrated that Rpn13C (Rpn13 residues 270-407) could disrupt the oligomerization of Uch37 by sequestering Uch37 and forming a Uch37-Rpn13 complex. Uch37 was activated in such a complex, exhibiting 12-fold-higher activity than Uch37 alone. Time-resolved SAXS (TR-SAXS) and FRET experiments supported the proposed mode of auto-inhibition and the activation mechanism of Uch37 by Rpn13. Rpn13 activated Uch37 by forming a 1:1 stoichiometric complex in which the active site of Uch37 was accessible to Ub.
Binding Sites ; Catalytic Domain ; Chromatography, Gel ; Crystallography, X-Ray ; Humans ; Membrane Glycoproteins ; chemistry ; genetics ; metabolism ; Nuclear Magnetic Resonance, Biomolecular ; Protein Binding ; Protein Conformation ; Protein Multimerization ; Scattering, Small Angle ; Ubiquitin Thiolesterase ; chemistry ; genetics ; metabolism ; Ultracentrifugation