Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0027819 (neuroblastoma)
 27,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Leukemia-inhibitory factor (LIF) is a neuropoietin able to regulate the differentiation and the survival of many cell types, which include some neuronal populations. The present study describes the genetic construction, expression, purification and properties of a diphtheria-toxin-related LIF gene fusion in which the native receptor-binding domain of diphtheria toxin was replaced with a gene encoding human LIF. The fusion protein expressed from the chimeric tox gene was designated DT-(1-389)-LIF-(2-184)-peptide. This fusion protein has a deduced molecular mass of 65980 Da and is formed by fusion of the first 389 amino acids of diphtheria toxin to amino acids 2-184 of mature human LIF, using a linker of 34 amino acids that includes six consecutive histidine residues. The latter span allows for single-step purification of the fusion protein by Ni(2+)-resin affinity chromatography. This linker provides a high degree of flexibility between the diphtheria toxin and LIF domains, thereby permitting aggregation-free refolding of the chimeric protein while bound to the affinity column. Both LIF and DT-(1-389)-LIF-(2-184)-peptide induced the phosphorylation of CLIP1 and CLIP2 in LIF-responsive neuroblastoma SH-N-BE cells. DT-(1-389)-LIF-(2-184)-peptide was selectively cytotoxic for cultured neuroblastoma cells bearing the LIF receptor, and for sympathetic neurons. The cytotoxic action of DT-(1-389)-LIF-(2-184)-peptide, like that of native diphtheria toxin, required receptor-mediated endocytosis, passage through an acidic compartment, and delivery of an ADP-ribosyltransferase to the cytosol of target cells. The latter point was confirmed by the fact that, while both LIF and DT-(1-389)-LIF-(2-184)-peptide increased c-fos mRNA expression in SH-N-BE cells, only LIF induced proenkephalin and c-fos promoter activities in cells transiently transfected with c-fos-chloramphenicol acetyltransferase and proenkephalin-chloramphenicol acetyltransferase fusion genes. Mutational analysis suggested that the C-terminal helix (helix D) of human LIF may, in part, constitute or contribute to the active site for LIF receptor binding and cell activation. The cytotoxic properties of DT-(1-389)-LIF-(2-184)-peptide may be useful in selectively depleting neuronal and immune cell populations that express the LIF beta receptor.
 ...
PMID:Synthesis, cytotoxic properties and effects on early and late gene induction of a chimeric diphtheria toxin-leukemia-inhibitory factor protein. 891 49

Amino acid changes in the envelope glycoproteins of Sindbis virus have been linked to neurovirulence; however, the molecular mechanisms by which these amino acid changes alter neurovirulence are not known. Recombinant-virus studies have mapped an important determinant of neurovirulence in adult mice to a single amino acid change, glutamine to histidine, at position 55 of the E2 glycoprotein (P. C. Tucker, E. G. Strauss, R. J. Kuhn, J. H. Strauss, and D. E. Griffin, J. Virol. 67:4605-4610, 1993). To investigate how histidine confers neurovirulence, we examined the various stages of the virus life cycle in neural (N18) and nonneural (BHK) cells. In BHK cells, recombinant viruses 633 (E255Q) and TE (E255H) replicated similarly. In contrast, in N18 neuroblastoma cells, TE established infection more efficiently, replicated faster, and achieved higher rates of virus release than did 633. Viral structural protein synthesis was similar in 633- and TE-infected BHK cells, while in N18 cells, structural protein synthesis was detected only in TE-infected cells at 6 h and remained higher for at least 16 h postinfection. Viral RNA synthesis was initiated more rapidly and was up to fivefold greater in TE- versus 633-infected N18 cells. Taken together with other data demonstrating minimal effects on virus binding and entry (P. C. Tucker, S. H. Lee, N. Bui, D. Martinie, and D. E. Griffin, J. Virol. 71:6106-6112, 1997), these data suggest that E2 position 55 plays an important role at early stages of infection of neural cells, thereby facilitating neurovirulence.
 ...
PMID:A single amino acid change in the E2 glycoprotein of Sindbis virus confers neurovirulence by altering an early step of virus replication. 922 4

We report on two children with malignancy who showed fungemia despite the antifungal treatment with fluconazole. Case 1 was a 7-year-old girl with a recurrence of stage IV neuroblastoma. She had profound neutropenia and fungemia developed after a month-long treatment with fluconazole. Her peripheral blood smear showed phagocytosis in the neutrophils and they were identified as fungi by immunofluorescence method (Fungi flora Y). She died two days after the diagnosis of fungemia. Rhodotorula rubra was isolated after her death. Case 2 was a 2-year-old boy with disseminated Langerhans cell histiocytosis. He had profound neuropenia and fungemia developed after treatment with fluconazole for 6 months. His peripheral blood smear also showed phagocytosis in the neutrophils and they were identified as fungi by Fungi flora Y. He was treated with intravenously administered amphotericin-B. However, he died 13 days after the diagnosis of fungemia. Candida guilliermondii was isolated after his death. Careful observation of the peripheral blood smear is important for early detection of fungi and Fungi flora Y is a quick and useful method to identify fungi. Fluconazole-resistant fungus should be considered when patients with neutorpenia are treated prophylactically with fluconazole for a long time.
 ...
PMID:[Phagocytosis of fungi in the peripheral blood neutrophils of two children with cancer during treatment with fluconazole]. 931 Dec 73

We encountered a patient with neuroblastoma showing remarkably high total LD activity (12,585 IU/l). His liver and heart function was normal. In the serum LD isoenzyme pattern, LD1 was increased, and LD2 extra band (LD2 ex) was observed on the negative pole side of LD2. However, LD2 ex was absent in erythrocytes of the patient, which demonstrates the exclusion of genetic factors. Neither the enzyme counter current method or immunofixation showed immune complexes, excluding anomalies. The LD isoenzyme in a metastatic lymphnode lesion before treatment showed increased LD1. The LD isoenzymes in the tissue, removed after 5 courses of chemotherapy, showed predominance of LD3 and absence of LD2 ex. Rapid decreases in the serum total LD activity and LD1 fraction and the disappearance of LD2 ex after chemotherapy suggest that these changes in the two LD fractions are associated with production of abnormal LD (LD2 ex) by the tumor.
 ...
PMID:[A case of neuroblastoma with abnormal LD isoenzyme]. 959 31

The growth rate of rodent embryonic neuroblasts and human neuroblastoma cell lines is regulated in part by autocrine or paracrine actions of neuropeptides of the family that includes vasoactive intestinal peptide (VIP), peptide histidine isoleucine (PHI), and pituitary adenylate cyclase-activating peptide (PACAP). These peptides act via seven transmembrane G-protein-linked receptors coupled to cAMP elevation, phospholipase C activation, intracellular Ca2+ release, and/or of mitogen-activated protein (MAP) kinase activation. Here we investigated the action of these peptides on the mouse neuroblastoma cell line Neuro2a. PHI and VIP inhibited proliferation at concentrations as low as 10(-13) M and 10(-10) M, respectively. In contrast, PACAP action was biphasic, with stimulation occurring at subnanomolar doses and inhibition at higher doses. Peptide actions were studied further by measuring cAMP and ERK1/2 MAP kinase activity and by assessing 3H-thymidine incorporation in conjunction with a panel of signal transduction pathways inhibitors. The data obtained indicated that the PHI-inhibitory and PACAP-stimulatory activities were mediated by corresponding changes in activity of the MAP kinase pathway and independent of protein kinase A (PKA) or protein kinase C (PKC). In contrast, the inhibitory actions of VIP and PACAP were specifically blocked by antagonists of PKA. Northern blot analysis revealed gene expression for only the PACAP-preferring (PAC1) receptor. However, binding experiments using 125I-labeled PACAP27, PHI, and VIP, demonstrated the presence of PACAP-preferring sites, bivalent VIP/PACAP sites, and PHI-binding sites that did not interact with VIP. The studies demonstrate potent regulatory actions of PACAP, PHI, and VIP on neuroblastoma cell proliferation which appear to be mediated by multiple subsets of receptors which differentially couple to MAP kinase and PKA signaling pathways.
 ...
PMID:Differential effects of peptide histidine isoleucine (PHI) and related peptides on stimulation and suppression of neuroblastoma cell proliferation. A novel VIP-independent action of PHI via MAP kinase. 967 97

The exo-N-acetyl-beta-d-glucosaminidase (EC 3.2.1.30) from thermotolerant Bacillus sp. NCIM 5120 is a homotetramer with a molecular mass of 240000 kDa. Chemical modification studies on the purified exo-N-acetyl-beta-d-glucosaminidase revealed the involvement of a single tryptophan, histidine and carboxylate, per monomer, in the catalytic activity of the enzyme. Spectral analysis and maintenance of total enzyme activities indicated that N-acetylglucosamine (competitive inhibitor) and p-nitrophenyl-N-acetyl-beta-d-glucosaminide (substrate) prevented the modification of a single essential tryptophan, histidine and carboxylate residue. Kinetic parameters of partially inactivated enzyme (by NBS/HNBB) showed the involvement of tryptophan in substrate binding while that of histidine (by photooxidation/DEPC) and carboxylate (by EDAC/WRK) in catalysis. The Bacillus sp. NCIM 5120 exo-N-acetyl-beta-d-glucosaminidase deviates from the reported N-acetyl-beta-d-glucosaminidases and beta-hexosaminidases that utilize anchimeric assistance in their hydrolytic mechanism.
 ...
PMID:Active site characterization of the exo-N-acetyl-beta-D- glucosaminidase from thermotolerant Bacillus sp. NCIM 5120: involvement of tryptophan, histidine and carboxylate residues in catalytic activity. 1008 93

The Ser122 --> Pro mutation in human nucleoside diphosphate kinase (NDK)-B/Nm23-H2 was recently found in melanoma cells. In comparison to the wild-type enzyme, steady state activity of NDKS122P with ATP and TDP as substrates was slowed down 5-fold. We have utilized transient kinetic techniques to analyze phosphoryl transfer between the mutant enzyme and various pairs of nucleoside triphosphates and nucleoside diphosphates. The two half-reactions of phosphorylation and dephosphorylation of the active site histidine residue (His118) were studied separately by making use of the intrinsic fluorescence changes which occur during these reactions. All apparent second order rate constants are drastically reduced, falling 5-fold for phosphorylation and 40-200-fold for dephosphorylation. Also, the reactivity of the mutant with pyrimidine nucleotides and deoxy nucleotides is more than 100-fold reduced compared with the wild-type. Thus, the rate-limiting step of the NDK-BS122P-catalyzed reaction is phosphoryl transfer from the phospho-enzyme intermediate to the nucleoside diphosphate and not phosphoryl transfer from the nucleoside triphosphate to the enzyme as was found for the wild-type protein. This results in a pronounced shift of the equilibrium between unphosphorylated and phosphorylated enzyme. Moreover, like the Killer-of-prune mutation in Drosophila NDK and the neuroblastoma Ser120 --> Gly mutation in human NDK-A/Nm23-H1, the Ser122 --> Pro substitution in NDK-B affects the stability of the protein toward heat and urea. These significantly altered properties may be relevant to the role of the mutant enzyme in various intracellular processes.
 ...
PMID:Human nucleoside diphosphate kinase B (Nm23-H2) from melanoma cells shows altered phosphoryl transfer activity due to the S122P mutation. 1040 Jun 30

Pineal and retinal melatonin synthesis is controlled by the enzymatic activity of arylalkylamine N-acetyltransferase (AA-NAT, EC 2.3.1.87), which is regulated by light/dark signals and circadian factors. This enzyme converts serotonin to N-acetylserotonin by the transfer of an acetyl group from acetyl coenzyme A. Endogenous AA-NAT instability during routine purification has made enzyme characterization difficult, but now a stable recombinant protein for AA-NAT has been synthesized to investigate the intrinsic biochemical properties of AA-NAT from a rat pineal cDNA encoding a 205 amino acid, 23 kilodalton protein, by using a glutathione-S-transferase (GST) fusion protein system. Recombinant GST-AA-NAT showed substrate specificity for arylalkylamines and stability at 4 degrees C; however, the enzyme activity was reduced by 40% upon preincubation at 37 degrees C for 2 hr. GST-AA-NAT is preferentially phosphorylated by either cyclic AMP- or cyclic GMP-dependent kinases in vitro, but no detrimental effect was observed on AA-NAT enzymatic activity. Among the metal cations tested in this study, Ca2+, Mg2+, Mn2+, Fe2+, and Co2 showed little or no inhibitory potency, while either 1 mM Zn2+ or 0.1 mM Cu2+ nearly abolished the enzymatic activity. GST-AA-NAT enzyme activity is also inhibited by reagents that are known biochemically to modify thiol groups (N-ethylmaleimide, NEM) and histidine residues (p-chloromercuribenzoate, NBS and diethyl pyrocarbonate, DEPC), suggesting the presence of essential cysteine and histidine moieties. Moreover, preincubation of acetyl CoA completely protects the recombinant AA-NAT from inactivation by NEM and DEPC, indicating that specific cysteine and histidine residues may be at the acetylation site. The conclusion is that the biochemical properties of rat recombinant AA-NAT is similar to the endogenous pineal and retinal AA-NAT with respect to the sensitivity to temperature, metal cations, as well as the thiol modification reagents. These data also suggest that the phosphorylation status of the AA-NAT does not affect enzymatic activity directly, and histidine residues are potentially important residues required for high catalytic activity.
 ...
PMID:Biochemical characterization of recombinant serotonin N-acetyltransferase. 1045 Oct 24

Pituitary adenylate cyclase activating polypeptide type I receptor (PACAPr) belongs to the novel subfamily of the G-protein coupled receptors with a long extracellular N-terminus, which functions as a major binding site for the PACAP. Three different N-terminal fragments of rat PACAPr were overexpressed in Escherichia coli and purified using His-tags or maltose-binding protein as anchors for affinity chromatography. The purified and refolded proteins were used for the production and screening of monoclonal antibodies (MAbs) to PACAPr. Fifteen hybridoma cell lines producing MAbs specific to PACAPr were generated and characterized. Epitope analysis by competitive enzyme-linked immunoadsorbent assay (ELISA) indicated the presence of two groups of overlapping epitopes in the N-terminal fragment of PACAPr. Reactivity of MAbs with SDS-denaturated and native rat PACAPr was demonstrated by immunoblotting and flow cytometric analysis using transiently transfected COS cells and stably transfected CHO cells expressing rat PACAPr. Each antibody was examined by immunoblotting for the ability to cross react with the human PACAPr in human neuroblastoma NB-OK cells and most of them were shown to recognize human PACAPr as effectively as rat PACAPr. MAbs against the N-terminal extracellular domain of PACAPr can be used for the immunochemical study of the receptor-ligand interaction and for the investigation of PACAPr distribution in normal and tumor tissues.
 ...
PMID:Production and characterization of monoclonal antibodies to pituitary adenylate cyclase activating polypeptide type I receptor. 1057 Dec 63

The prion protein (PrP) has been proposed to display sequence and structural similarities to membrane-anchored signal peptidases [Glockshuber et al. (1998) FEBS Lett. 426, 291-296]. We have investigated the role of Tyr-128 and His-177 in the proteolytic fragmentation of murine PrP by mutating these residues to Phe and Leu, respectively, and expressing the resultant mutants in the human neuroblastoma SH-SY5Y. Both PrP-Y128F and PrP-H177L were expressed at the cell surface as glycosyl-phosphatidylinositol-anchored forms and were localised in detergent-insoluble membrane domains similar to wild type PrP. Following deglycosylation, the 19 kDa proteolytic fragment PrP-II was present in cells expressing either mutant, indicating that Tyr-128 and His-177 are not involved in the proteolytic fragmentation of PrP.
 ...
PMID:Proteolytic fragmentation of the murine prion protein: role of Tyr-128 and His-177. 1060 36


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>