Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q07644 (polypeptide)
 72,197 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Molecular cloning of the polypeptide component of the Rel-related human p75 nucleoprotein complex has revealed its identity with the 65-kDa (p65) subunit of NF-kappa B. Functional analyses of chimeric proteins composed of NF-kappa B p65 C-terminal sequences linked to the DNA-binding domain of the yeast GAL4 polypeptide have indicated that the final 101 amino acids of NF-kappa B p65 comprise a potent transcriptional activation domain. Transient transfection of human T cells with an expression vector encoding NF-kappa B p65, but not NF-kappa B p50, produced marked transcriptional activation of a basal promoter containing duplicated kappa B enhancer motifs from the long terminal repeat of type 1 human immunodeficiency virus. These stimulatory effects of NF-kappa B p65 were synergistically enhanced by coexpression of NF-kappa B p50 but were completely inhibited by coexpression of the v-rel oncogene product. Together, these functional studies demonstrate that NF-kappa B p65 is a transactivating subunit of the heterodimeric NF-kappa B complex and serves as one cellular target for v-Rel-mediated transcriptional repression.
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PMID:The 65-kDa subunit of human NF-kappa B functions as a potent transcriptional activator and a target for v-Rel-mediated repression. 154 86

The 75 kDa heat-shock-related protein (p75) of Plasmodium falciparum is an abundant, highly conserved, merozoite surface protein. A bacterial clone, C7, produces a polypeptide (C7Ag) of approximately 30 kDa representing the C-terminal 40% of p75. In several species of animals, the C7Ag stimulated high titre IgG antibodies which cross-react with p75. Two major portions of the C7Ag, theoretically predicted to have strong secondary structural preferences, were modelled with four synthetic peptides. An alpha-helical, hydrophilic region, modelled with a 28-mer, proved a poor immunogen in guinea-pigs and several strains of inbred mice, even though it had been a strong immunogen in rabbits. A disulphide-bonded region of the C7Ag was modelled with three peptides of increasing length, namely 49-, 64- and 76-amino acid residues. In general, the order of immunogenicity was 49 less than 64 less than 76-mer. Antibodies to the 76-mer and the 64-mer reacted strongly with the native parasite protein. The data also suggested that the 76-mer was a good model for the region of the molecule it was made to represent.
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PMID:Antibody responses stimulated in rabbits, guinea-pigs and mice by recombinant and synthetic portions of a 75 kDa malarial merozoite protein. 162 18

Studies of NF-kappa B suggest that this enhancer binding activity corresponds to a family of at least four proteins (p50, p55, p75, and p85) differentially induced with biphasic kinetics during T cell activation. While p55 and p50 are closely related to the 50 kd DNA binding subunit of NF-kappa B, p75 and p85 exhibit DNA binding properties that distinguish them from this 50 kd polypeptide and its regulatory subunits I kappa B and p65. All four members of this kappa B-specific protein family are structurally related to the v-Rel oncoprotein and one, p85, appears identical to human c-Rel. v-Rel, but not nontransforming v-Rel mutants, binds to the kappa B enhancer and inhibits NF-kappa B-activated transcription from the IL-2 receptor alpha promoter and HIV-1 LTR. These findings suggest a Rel-related family of kappa B enhancer binding proteins and raise the possibility that the transforming activity of v-Rel is linked to its inhibitory action on cellular genes under NF-kappa B control.
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PMID:The v-rel oncogene encodes a kappa B enhancer binding protein that inhibits NF-kappa B function. 222 78

The human high-affinity receptor for interleukin 2 (IL-2) has been proposed as being a membrane complex composed of at least two distinct polypeptide chains: p55 (alpha chain), recognized by the anti-Tac monoclonal antibody (mAb), and p75 (beta chain), both of which are capable of binding IL-2. Whereas the alpha chain itself has been shown to be nonfunctional, the beta chain appears to be pivotal in the IL-2 signal transduction, although the beta chain is otherwise poorly characterized. Three beta chain-specific mAbs, designated Mik-beta 1, -beta 2, and -beta 3, were developed. Mik-beta 1 and -beta 2 completely inhibited the IL-2 binding to the beta chain, whereas Mik-beta 3 immunoprecipitated the beta chain crosslinked with 125I-labeled IL-2. The beta chain immunoprecipitated by these mAbs was revealed to have a Mr of 68,000-72,000. High-affinity IL-2 binding was completely abolished by Mik-beta 1. Although IL-2-dependent T-cell growth at high IL-2 concentrations was not inhibited by the anti-Tac, it was almost completely inhibited by Mik-beta 1 in the presence of the anti-Tac. These results clearly indicate that the beta chain is an indispensable component to the high-affinity IL-2 receptor and is responsible for the IL-2 signal transduction. The beta chain was found to be constitutively expressed without the alpha chain on the surface of peripheral blood Leu-19+ natural killer cells.
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PMID:Characterization of the interleukin 2 receptor beta chain using three distinct monoclonal antibodies. 246 93

Recent studies have shown that IL-2R are composed of at least two polypeptide chains of 55 kDa (Tac or alpha-chain) and 70 to 75 kDa (p70 or beta-chain). The association of both chains forms high affinity IL-2R, whereas each chain alone binds IL-2 with a low (alpha-chain) or intermediate (beta-chain) affinity. So far, the p70 peptide has been found, in the absence of the Tac peptide, on the surface of lymphoid cells of T, B, or NK lineage. In this study, we investigated whether leukemic cells of various hemopoietic lineages expressed the p70 IL-2-binding protein. We found that both fresh leukemic cells obtained from patients, and cells from established leukemic lines of T cells, B cell, and myeloid origin constitutively expressed a p70 IL-2-binding protein on their surface, as detected by affinity cross-linking of radioiodinated IL-2. IL-2 binding and cross-linking to these cells was completely inhibited in the presence of an excess unlabeled rIL-2, but not with an anti-Tac mAb. Binding experiments on pre-B and myeloid cell lines revealed intermediate affinity IL-2R, whereas both high and intermediate affinity IL-2R were detected in T leukemic cells. The intermediate affinity binding of 125I-rIL-2 to the leukemic cell lines MOLT4 and Reh6 was inhibited by the TU27 mAb, which recognized the p75 chain of IL-2R. Moreover, the TU27 mAb could stain the K562, KM3, and MOLT4 (weakly) cell lines by indirect immunofluorescence. A high dose of rIL-2 (400 U/ml) enhanced the proliferation of cells from one out of three patients with acute myeloblastic leukemia, but it did not induce differentiation of the cells in any of three cases. Thus the finding of p70 IL-2-binding molecules on immature lymphoid and nonlymphoid hemopoietic cells should disclose new biologic functions for IL-2.
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PMID:Presence of a p70 IL-2-binding peptide on leukemic cells from various hemopoietic lineages. 278 58

The growth of mature T lymphocytes is regulated by interaction between interleukin-2 (IL-2) and its receptor. Three distinct binding sites for IL-2, namely low- (Kd 10 nM), intermediate- (Kd 100 pM) and high- (Kd 10 pM) affinity sites, have been found on human and primate T lymphocytes. Chemical crosslinking of labelled IL-2 to human T cells shows that two polypeptide chains, p55 (L chain) and p75 (H chain), bind IL-2 with low and intermediate affinities respectively. The high-affinity binding was shown to arise from ternary complex formation of IL-2, L and H chains. Construction of mutants of the L-chain complementary DNA indicated that the L chain is not directly involved in growth signal transduction. Nevertheless, expression of the IL-2 receptor L chain is tightly regulated by antigen or mitogen stimulation. To investigate the L chain function, we have produced transgenic mice using human L-chain cDNA of the IL-2 receptor under the control of a constitutive promoter. Studies on the L-chain transgenic mice showed that functionally active IL-2 receptors with high affinity were expressed on unstimulated spleen and thymus cells. The results indicate that the H chain of the IL-2 receptor is constitutively expressed in T cells.
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PMID:Expression of functional interleukin-2 receptors in human light chain/Tac transgenic mice. 282 38

A 75-kilodalton polypeptide has been identified which copurifies with karyoskeletal protein-enriched fractions prepared from Drosophila melanogaster embryos. Results of indirect immunofluorescence experiments suggest that this protein, here designated p75, is primarily associated with puffed regions of larval salivary gland polytene chromosomes. In nonpolytenized Schneider 2 tissue culture cells, p75 appeared to be localized throughout the nuclear interior during interphase. In mitotic cells, p75 was redistributed diffusely. A possible role for karyoskeletal elements in transcriptional regulation is discussed.
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PMID:p75, a polypeptide component of karyoskeletal protein-enriched fractions associated with transcriptionally active loci of Drosophila melanogaster polytene chromosomes. 313 49

To study pathogenic T helper cells in myasthenia gravis (MG) reacting against the acetylcholine receptor (AChR), we have previously selected five CD4+ T cell lines/clones from MG patients (or healthy controls) against full-length recombinant human AChR alpha subunit (alpha 1-437); these can all recognize AChR solubilized from human muscle. Recently, T cells selected with pooled AChR subunit synthetic peptides have shown greater heterogeneity than above. Hoping to validate that, we have characterized three MG and six control T cell lines selected with pooled peptides (averaging 33 residues long) covering the alpha subunit sequence; recurring responses to three particular peptides each showed preferred HLA class II restrictions--p75-115/DR4, p138-167/DR4, and p309-344/DR3 (or DR52a). However, none of three lines from MG patients recognized p138-167--even one from a previous responder to this epitope in full-length alpha 1-437; otherwise they resembled those from controls. Moreover, no peptide-selected line responded significantly to whole AChR, alpha 1-437, or even to shorter polypeptides sharing one terminus with the peptide, suggesting specificity for epitopes not naturally processed by APCs from blood. Of 20 sublines maintained with individual peptides, at least 10 responded to independently synthesized overlapping sequences, but four others depended on contaminants in the original peptides. A single line did recognize one longer polypeptide, but only after tryptic digestion; the processing of this cryptic epitope was evidently the limiting factor here rather than its concentration or the T cell sensitivity. Therefore, while synthetic peptides are essential for mapping epitopes, assessment of the pathogenic MG T cell repertoire requires full-length Ag processed naturally.
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PMID:Peptide-selected T cell lines from myasthenia gravis patients and controls recognize epitopes that are not processed from whole acetylcholine receptor. 756 Oct 69

A peptide corresponding to residues 70-80 of the TNF-alpha polypeptide was synthesized and shown to enhance human PMN-mediated killing of Plasmodium falciparum in vitro and reduced the Plasmodium chabaudi parasitemia in mice. Studies of the mechanism of action showed that the peptide, TNF(70-80), stimulated and primed PMN for an increased respiratory burst and release of granule constituents in response to a second agonist. The PMN-stimulatory activity of the peptide was inhibited by mAbs against the p55 and p75 TNF receptors and a TNF-neutralizing mAb. Analysis of PMN receptor expression showed that CR3 (CD18/CD11b) and Fc gamma RIII were upregulated by TNF(70-80), which was consistent with the peptide's ability to enhance parasite killing by PMN. The peptide, unlike TNF, did not increase the expression of adhesion molecules on endothelial cells and failed to promote binding of P. falciparum-infected erythrocytes to endothelial cells. TNF(70-80) also inhibited the TNF-induced increase in adhesion of P. falciparum-infected erythrocytes to endothelial cells. The results demonstrate that the host-protective effects of TNF can be retained while toxic effects are eliminated using a selected, characterized subunit of the cytokine.
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PMID:A synthetic tumor necrosis factor-alpha agonist peptide enhances human polymorphonuclear leukocyte-mediated killing of Plasmodium falciparum in vitro and suppresses Plasmodium chabaudi infection in mice. 773 94

Interleukin-2, a polypeptide lymphokine that induces proliferation of antigen- or mitogen-stimulated T cells, was first described as "T-cell growth factor" by Morgan et al. in 1976. IL-2 is one of several lymphocyte-produced messenger regulatory molecules that modulate immunocyte function. The main secretory source of IL-2 is the T-helper cell. In 1983, Taniguchi and colleagues isolated a human IL-2 complementary DNA clone from a high-producer Jurkat leukemic cell line, and established its nucleotide sequence. In 1984, Rosenberg et al. described the isolation of cDNA clones of the gene for IL-2 from the Jurkat cell line, its expression in Escherichia coli and its biological characteristics. The mature secreted protein contains 133 amino acids, constituting a calculated molecular weight of 15,420. Since the discovery of IL-2 and its T-cell growth-promoting activity, extensive research has revealed the complex nature of its immunologic effects, both in vitro and in vivo. The immunopotentiating activities, encouraging in vitro results, plus successful therapy of animal tumors in preclinical studies provided the rationale for investigation of IL-2 in patients with advanced malignancy and immunodeficiencies. The IL-2 receptor has been found to have an unexpected by unusual structure in that it is composed of two separate chains designated alpha (p75) and beta (p55). Recently, it has been discovered the 3rd gamma-chain by Sugamura et al. Clinical trials of IL-2 in patients with cancer have been done by many researchers. The clinical trials has reviewed briefly.
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PMID:[Interleukin-2 (IL-2)]. 815


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