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:2.7.10.1 (ERK)
95,504 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In an attempt to define the binding of staphylococcal enterotoxin D (SED) to the T cell receptor Vbeta (TCR Vbeta) and major histocompatibility complex (MHC) class II molecules, site-directed mutagenesis has been used to introduce alanine substitutions at Asn23, Phe45, Leu59, Asn61, Ile92 and Phe203 in SED. SED-N23A (SEA with Asn23 replaced with alanine) and SED-F45A mutants exhibit a significantly reduced ability to induce T cell proliferation. However, SED-L59A, SED-N61A, SED-I92A and SED-F203A mutants exhibit the normal mitogenic activity. The ability binding to MHC class II and the TCR Vbeta specificity of SED-N23A and SED-F45A were then detected. SED-N23A, but not SED-F45A, was able to compete effectively with FITC-conjugated SED for binding to Raji cells. This finding indicates that the mitogenic activity defection of SED-N23A is not due to poor binding to SED-MHC class II molecules. When stimulated with SED-N23A, T cells bearing TCR Vbeta5 were significantly reduced. When stimulated with SED-F45A, T cells bearing TCR Vbeta5, TCR Vbeta8 and TCR Vbeta12.1 were all significantly reduced. These results suggest Asn23 is an important residue involved SED interacting with TCR Vbeta; Phe45 is required for effective interaction with MHC class II molecules; and the ability of SED stimulating certain TCR Vbeta+ T cells is dependent on Phe45 binding to MHC class II molecules.
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PMID:Mutational analysis of the binding of staphylococcal enterotoxin D to the T cell receptor Vbeta chain and major histocompatibility complex class II. 1648 Oct 46

In addition to their essential role in antigen presentation, major histocompatibility complex (MHC) class II molecules have been described as the receptor associated with signal transduction regulating B-cell function. In previous experiments, we found that cross-linking of MHC class II molecules with corresponding anti-MHC class II antibodies inhibited NF-kappaB-activated signaling pathways associated with the proliferation and differentiation of the LPS-stimulated primary and resting B-cell line, 38B9. We also found that exposure to the anti-MHC class II antibody reduced the production of ROS, which function as secondary signal transducers, in the phorbol 12,13-dibutyrate (PDBU)-treated (but not in the LPS-treated) resting B-cell line. In this study, we investigated the molecular mechanisms in the ROS-associated signaling pathway leading to PDBU-induced NF-kappaB activation that results in B-cell differentiation and speculated that the signaling pathway was inhibited by exposure to the anti-MHC class II antibody. We also found that this inhibition was mediated through down-regulation of the activated Rac/ROS-associated ERK/p38 MAPK signaling pathway in PDBU-treated 38B9 cells. Collectively, these findings suggest that ROS-associated molecules are involved in MHC class II-associated negative signal transduction in resting B cells.
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PMID:Cross-linking of MHC class II molecules interferes with phorbol 12,13-dibutyrate-induced differentiation of resting B cells by inhibiting Rac-associated ROS-dependent ERK/p38 MAP kinase pathways leading to NF-kappaB activation. 1701 24

This study evaluated the response of rat brain to 2 degradable polymers (poly (L-lactic-co-glycolic acid) (PLGA), and poly(epsilon-caprolactone) (PCL)), two common materials in tissue engineering. PLGA has been extensively studied in the brain for controlled drug release as injectable microspheres and is generally accepted as biocompatible in that capacity. Biocompatibility in other forms and for different functions in the brain has not been widely studied. PCL was chosen as an alternative to PLGA for its slower degradation and less-acidic pH upon degradation. Porous scaffolds were made from both polymers and implanted into rat cerebral cortex for 1 and 4 weeks. Morphology, defect size, activation of microglia (OX-42) and astrocytes (glial fibrillary acidic protein (GFAP)), infiltration of activated macrophages (major histocompatibility complex (MHC)-II), and ingrowth of neurons (beta-tubulin type III (Tuj-1)) and progenitor cells (nestin) were analyzed using hematoxylin and eosin staining and immunofluorescence. PCL induced a lower inflammatory response than PLGA, as demonstrated by lower MHC-II and GFAP expression and greater ingrowth. Both polymers alleviated astrocytic activation and prevented enlargement of the defect. Tuj-1-, nestin-, and GFAP-positive cells were observed growing on both polymers at the peripheries of the sponge implants, demonstrating their permissiveness to neural ingrowth. These findings suggest that both polymers attenuate secondary death and scarring and that PCL might have advantages over PLGA.
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PMID:Poly(epsilon-caprolactone) and poly (L-lactic-co-glycolic acid) degradable polymer sponges attenuate astrocyte response and lesion growth in acute traumatic brain injury. 1765 92

Novel Ab-based immunotherapeutic strategies have exploited T-cell receptor-like chimeric immune receptors (CIR) expressed on the surface of transduced human peripheral blood mononuclear cell (PBMC) to redirect potent non-major histocompatibility complex-dependent cytotoxicity to tumor cells expressing a tumor-associated antigens. We transduced human PBMC with 2 fully human CIRs that trigger through the zeta-chain of CD3 and contain either one of two human scFv specific for the same epitope on the extracellular domain of HER2 but with distinctly different affinities (KD 1616 and 1 nM) for this antigen. Potent direct CIR-mediated killing and in vitro tumor growth inhibition mediated by transduced PBMC were observed against targets expressing different levels of HER2. High-affinity CIR showed stronger ability to bind Ag and retain binding than low-affinity CIR. When lytic potential of the 2 CIRs was evaluated, their efficiency was comparable under conditions of high CIR and Ag expression, whereas low-affinity CIR was more efficient than high-affinity CIR in conditions of limiting Ag and CIR expression levels. When tumor growth inhibition was evaluated, Ag and CIR levels, rather than CIR affinity appeared relevant. Ag-driven CIR activation resulted in the production of soluble factors mediating efficient bystander effect. By carefully defining CIR surface expression and increasing affinity for a specific target antigen, it may be possible to selectively exclude CIR-mediated activity against targets expressing low levels of antigen, as normal cells. On the contrary, low antigen-expressing tumor variants could be eliminated by decreasing CIR affinity. Tuning CIR expression and affinity might help in discriminating different biologic contexts.
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PMID:Redirected activity of human antitumor chimeric immune receptors is governed by antigen and receptor expression levels and affinity of interaction. 1789 61

Formaldehyde is frequently used in indoor household and occupational environments. Inhalation of formaldehyde invokes an inflammatory response, including a variety of allergic signs and symptoms. Therefore, formaldehyde has been considered as the most prevalent cause of sick building syndrome, which has become a major social problem, especially in developing urban areas. Further formaldehyde is classified as a genotoxicant in the respiratory tract of rats and humans. To better understand the molecular mechanisms involved in formaldehyde intoxication, we sought differentially regulated genes by formaldehyde exposure to Hs 680.Tr human trachea cells, using polymerase chain reaction (PCR)-based suppression subtractive hybridization. We identified 27 different formaldehyde-inducible genes, including those coding for the major histocompatibility complex, class IA, calcyclin, glutathione S-transferase pi, mouse double minute 2 (MDM2), platelet-derived growth factor receptor alpha, and which are known to be associated with cell proliferation and differentiation, immunity and inflammation, and detoxification. Induction of these genes by formaldehyde treatment was confirmed by reverse transcription PCR and western blot analysis. Further, the expression of calcyclin, glutathione S-transferase pi, PDGFRA and MDM2 were significantly induced in the tracheal epithelium of Sprague Dawley rats after formaldehyde inhalation. Our results suggest that the elevated levels of these genes may be associated with the formaldehyde-induced toxicity, and that they deserve evaluation as potential biomarkers for formaldehyde intoxication.
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PMID:Identification of formaldehyde-responsive genes by suppression subtractive hybridization. 1804 64

Nonclassical major histocompatibility complex (MHC) class I molecule human leukocyte antigen (HLA)-G is normally expressed on the placental cells, especially fetal endothelial cells and invasive cytotrophoblast cells at the maternal-fetal interface. This antigen meditates immune tolerance in pregnancy through interaction with immune cells including natural killer (NK) cells. In this study, we investigated the mechanisms underlying HLA-G1-mediated inhibition of NK cytotoxicity using HLA-G1-transfected K562 cells and NK92 cells. We found that inhibition of NK cytotoxicity by HLA-G1 was associated with decreased formation of NK-target cell conjugates and defective formation of immunologic synapse, as characterized by actin depolarization and perforin immobilization in nonactive NK cells. HLA-G1 engagement induced dephosphorylation of Vav by tyrosine phosphatase-1 (SHP-1), and thus blocked the Syk-->MEK/ERK activating signaling pathway in activating NK cells. These results indicate that HLA-G1 inhibits NK cytotoxicity by blocking activating signal transduction pathway, which is required for the formation of activating immunologic synapse.
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PMID:Human leukocyte antigen-G1 inhibits natural killer cytotoxicity through blocking the activating signal transduction pathway and formation of activating immunologic synapse. 1829 71

This year marks the 25th anniversary of the first Annual Review of Immunology article to describe features of the T cell antigen receptor (TCR). In celebration of this anniversary, we begin with a brief introduction outlining the chronology of the earliest studies that established the basic paradigm for how the engaged TCR transduces its signals. This review continues with a description of the current state of our understanding of TCR signaling, as well as a summary of recent findings examining other key aspects of T cell activation, including cross talk between the TCR and integrins, the role of costimulatory molecules, and how signals may negatively regulate T cell function.Acronyms and DefinitionsAdapter protein: cellular protein that functions to bridge molecular interactions via characteristic domains able to mediate protein/protein or protein/lipid interactions Costimulation: signals delivered to T cells by cell surface receptors other than the TCR itself that potentiate T cell activation cSMAC: central supramolecular activation cluster Immunoreceptor tyrosine-based activation motif (ITAM): a short peptide sequence in the cytoplasmic tails of key surface receptors on hematopoietic cells that is characterized by tyrosine residues that are phosphorylated by Src family PTKs, enabling the ITAM to recruit activated Syk family kinases Inside-out signaling: signals initiated by engagement of immunoreceptors that lead to conformational changes and clustering of integrins, thereby increasing the affinity and avidity of the integrins for their ligands NFAT: nuclear factor of activated T cells PI3K: phosphoinositide 3-kinase PKC: protein kinase C PLC: phospholipase C pMHC: peptide major histocompatibility complex (MHC) complex pSMAC: peripheral supramolecular activation cluster PTK: protein tyrosine kinase Signal transduction: biochemical events linking surface receptor engagement to cellular responses TCR: T cell antigen receptor
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PMID:T cell activation. 1913 16

The application of the peptide-linked beta2-microglobulin (beta2m) strategy is limited in some cases due to the incompatibility between the sequences of the peptides and the restriction sites of the plasmid vectors. An isocaudamer technique was adapted to overcome this restriction. Three peptide-linked beta2m genes, HBc(18-27)-hbeta2m gene, OVA(257-264)-mbeta2m gene and HER2/neu(369-377)-mbeta2m gene, were inserted into the pET28a vectors with this technique. The corresponding proteins were expressed in Escherichia coli with yields of over 50 mg/l culture and purities of over 80%. This strategy facilitates the construction of peptide-linked beta2m molecules and will simplify the preparation of major histocompatibility complex-peptide complexes.
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PMID:Cloning and expression of three peptide-linked beta2-microglobulin molecules in Escherichia coli with an isocaudamer technique. 1922 79

Rat major histocompatibility complex (MHC) class II molecules RT1.B(l) (DQ-like) and RT1.D(l) (DR-like) were cloned from the LEW strain using reverse transcription-polymerase chain reaction and expressed in mouse L929 cells. The transduced lines bound MHC class II-specific monoclonal antibodies in an MHC-isotype-specific manner and presented peptide antigens and superantigens to T-cell hybridomas. The T-cell-hybridomas responded well to all superantigens presented by human MHC class II, whereas the response varied considerably with rat MHC class II-transduced lines as presenters. The T-cell hybridomas responded to the pyrogenic superantigens Staphylococcus enterotoxin B (SEB), SEC1, SEC2 and SEC3 only at high concentrations with RT1.B(l)-transduced and RT1.D(l)-transduced cells as presenters. The same was true for streptococcal pyrogenic exotoxin A (SPEA), but this was presented only by RT1.B(l) and not by RT1.D(l). SPEC was recognized only if presented by human MHC class II. Presentation of Yersinia pseudotuberculosis superantigen (YPM) showed no MHC isotype preference, while Mycoplasma arthritidis superantigen (MAS or MAM) was presented by RT1.D(l) but not by RT1.B(l). Interestingly, and in contrast to RT1.B(l), the RT1.D(l) completely failed to present SEA and toxic shock syndrome toxin 1 even after transduction of invariant chain (CD74) or expression in other cell types such as the surface MHC class II-negative mouse B-cell lymphoma (M12.4.1.C3). We discuss the idea that a lack of SEA presentation may not be a general feature of RT1.D molecules but could be a consequence of RT1.D(l)beta-chain allele-specific substitutions (arginine 80 to lysine, asparagine 82 to aspartic acid) in the extremely conserved region flanking the Zn(2+)-binding histidine 81, which is crucial for high-affinity SEA-binding.
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PMID:Superantigen-presentation by rat major histocompatibility complex class II molecules RT1.Bl and RT1.Dl. 1974 Mar 18

Natural-killer group 2, member D (NKG2D) binds to a variety of ligands, including the major histocompatibility complex (MHC) class I chain-related proteins (MIC) and UL16-binding proteins (ULBP). It is regarded as a co-activating receptor on NK cells, having an important role in the cell-mediated immune response to tumours. We studied the influence of interleukin (IL)-10 on the regulation of MIC and ULBP expression on melanoma cells, and its effect on the cytotoxic function of NK cells in vitro. Here, we show that, in the presence of IL-10, FMS mel and BL mel cell lines decreased MICA and ULBP2 surface expression, whereas MHC class I did not change substantially on the cell surface. MICA mRNA levels decreased in IL-10-treated FMS and IL-10-transduced BL cell lines. Interestingly, we observed that MICB surface expression and its mRNA levels increased upon IL-10 treatment in a melanoma cell line. These changes in NKG2D ligands surface expression patterns owing to IL-10 treatment resulted in an effect on lysis susceptibility mediated by lymphocyte-activated killer cells, as tumour cell lines that displayed a higher decrease of MICA on their surface had lower levels of lysis. In addition, expression of CD107a was downregulated on the surface of NK cells following stimulation with IL-10-treated FMS cells. Our results suggest a novel function for IL-10 in the modulation of NKG2D ligand expression and in the control of cytotoxicity mediated by NKG2D/NKG2D ligand axis.
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PMID:Interleukin 10 decreases MICA expression on melanoma cell surface. 2071 39


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