I Protein (i + protein)

Distribution by Scientific Domains

Kinds of I Protein

  • class i protein


  • Selected Abstracts


    CPT-11 May Provide Therapeutic Efficacy for Esophageal Squamous Cell Cancer and the Effects Correlate with the Level of DNA Topoisomerase I Protein

    CANCER SCIENCE, Issue 12 2001
    Yasuaki Nakajima
    CPT-11 is a potent anti-cancer drug and a specific inhibitor of DNA topoisomerase I (Topo I). In this study, we aim to evaluate the effects of CPT-11 on esophageal squamous cell cancers (ESCC) and to determine the correlation between the effects and the levels of Topo I expression. We examined the growth-inhibitory effect caused by SN-38, an active metabolite of CPT-11, in 14 human ESCC cell lines established from 10 primary and 4 metastatic lesions. CPT-11 was considered effective against 5 cell lines from primary lesions and one from metastatic lesions, and thus may show therapeutic efficacy against both primary and metastatic ESCC tumors. Although Topo I mRNA levels in these 14 ESCC cell lines, as quantitated by northern blot analysis, showed no correlation with the IC50 values, Topo I protein levels, as quantitated by western blot analysis, showed an inverse correlation with the IC50 values. Topo I protein levels could be an indicator of sensitivity to CPT-11. We also determined Topo I protein levels in 40 ESCC tumors and matched normal mucosae. Thirty-four tumors showed 1.2-22.3-fold increases in Topo I levels. Two patients receiving pre-operative chemotherapy and one receiving radiotherapy exhibited increased Topo I protein levels in their tumor lesions. It appeared that CPT-11 could provide selective therapeutic efficacy against ESCC tumors. CPT-11 may be effective for the treatment of metastatic ESCC tumors and as a second-line anti-cancer drug for ESCC. [source]


    Fabrication of Oriented Multilayers of Photosystem I Proteins on Solid Surfaces by Auto-Metallization,

    ADVANCED MATERIALS, Issue 2 2008
    L. Frolov
    AFM phase image of PS I (Top) and platinized PS I (bottom) monolayers. The Pt patches serve as junctions for fabrication of oriented multilayer by covalent binding of cysteine mutants through the formation of sulfide bonds with the Pt. A larger absorption cross section and the serial arrangement resulted in an increase in the photopotential generated by the dry multilayers. [source]


    Solution structure of a hydrophobic analogue of the winter flounder antifreeze protein

    FEBS JOURNAL, Issue 4 2002
    Edvards Liepinsh
    The solution structure of a synthetic mutant type I antifreeze protein (AFP I) was determined in aqueous solution at pH 7.0 using nuclear magnetic resonance (NMR) spectroscopy. The mutations comprised the replacement of the four Thr residues by Val and the introduction of two additional Lys-Glu salt bridges. The antifreeze activity of this mutant peptide, VVVV2KE, has been previously shown to be similar to that of the wild type protein, HPLC6 (defined here as TTTT). The solution structure reveals an ,,helix bent in the same direction as the more bent conformer of the published crystal structure of TTTT, while the side chain ,1 rotamers of VVVV2KE are similar to those of the straighter conformer in the crystal of TTTT. The Val side chains of VVVV2KE assume the same orientations as the Thr side chains of TTTT, confirming the conservative nature of this mutation. The combined data suggest that AFP I undergoes an equilibrium between straight and bent helices in solution, combined with independent equilibria between different side chain rotamers for some of the amino acid residues. The present study presents the first complete sequence-specific resonance assignments and the first complete solution structure determination by NMR of any AFP I protein. [source]


    Identification and functional analysis of the gene for type I myosin in fission yeast

    GENES TO CELLS, Issue 3 2001
    Mika Toya
    Background Type I myosin is highly conserved among eukaryotes, and apparently plays important roles in a number of cellular processes. In the budding yeast, two myosin I species have been identified and their role in F-actin assembly has been inferred. Results We cloned the fission yeast myo1 gene, which apparently encoded a myosin I protein. Disruption of myo1 was not lethal, but it caused growth retardation at high and low temperatures, sensitivity to a high concentration of KCl, and aberrance in cell morphology associated with an abnormal distribution of F-actin patches. An abnormal deposition of cell wall materials was also seen. Homothallic myo1, cells could mate, but heterothallic myo1, cells were poor in conjugation. Myo1p was necessary for the encapsulation of spores. The tail domain of Myo1p was pivotal for its function. Calmodulin could bind to Myo1p through the IQ domain at the neck. Conclusions Myo1p appears to control the redistribution of F-actin patches during the cell cycle. Loss of Myo1p function is likely to slow down the actin assembly/disassembly process, which results in a failure of the actin cycle to catch up with other events in both the mitotic and meiotic cell cycles, including extension of the conjugation tubes. [source]


    Solvent models for protein,ligand binding: Comparison of implicit solvent poisson and surface generalized born models with explicit solvent simulations

    JOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 6 2001
    Linda Yu Zhang
    Abstract Solvent effects play a crucial role in mediating the interactions between proteins and their ligands. Implicit solvent models offer some advantages for modeling these interactions, but they have not been parameterized on such complex problems, and therefore, it is not clear how reliable they are. We have studied the binding of an octapeptide ligand to the murine MHC class I protein using both explicit solvent and implicit solvent models. The solvation free energy calculations are more than 103 faster using the Surface Generalized Born implicit solvent model compared to FEP simulations with explicit solvent. For some of the electrostatic calculations needed to estimate the binding free energy, there is near quantitative agreement between the explicit and implicit solvent model results; overall, the qualitative trends in the binding predicted by the explicit solvent FEP simulations are reproduced by the implicit solvent model. With an appropriate choice of reference system based on the binding of the discharged ligand, electrostatic interactions are found to enhance the binding affinity because the favorable Coulomb interaction energy between the ligand and protein more than compensates for the unfavorable free energy cost of partially desolvating the ligand upon binding. Some of the effects of protein flexibility and thermal motions on charging the peptide in the solvated complex are also considered. © 2001 John Wiley & Sons, Inc. J Comput Chem 22: 591,607, 2001 [source]


    Proteomic DIGE analysis of the mitochondria-enriched fraction from aged rat skeletal muscle

    PROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 24 2009
    Kathleen O'Connell
    Abstract Skeletal muscle aging is associated with a loss in tissue mass and contractile strength, as well as fiber type shifting and bioenergetic adaptation processes. Since mitochondria represent the primary site for energy generation via oxidative phosphorylation, we investigated potential changes in the expression pattern of the mitochondrial proteome using the highly sensitive DIGE approach. The comparative analysis of the mitochondria-enriched fraction from young adult versus aged muscle revealed an age-related change in abundance for 39 protein species. MS technology identified the majority of altered proteins as constituents of muscle mitochondria. An age-dependent increase was observed for NADH dehydrogenase, the mitochondrial inner membrane protein mitofilin, peroxiredoxin isoform PRX-III, ATPase synthase, succinate dehydrogenase, mitochondrial fission protein Fis1, succinate-coenzyme A ligase, acyl-coenzyme A dehydrogenase, porin isoform VDAC2, ubiquinol-cytochrome c reductase core I protein and prohibitin. Immunoblotting, enzyme testing and confocal microscopy were used to validate proteomic findings. The DIGE-identified increase in key mitochondrial elements during aging agrees with the concept that sarcopenia is associated with a shift to a slower contractile phenotype and more pronounced aerobic-oxidative metabolism. This suggests that mitochondrial markers are reliable candidates that should be included in the future establishment of a biomarker signature of skeletal muscle aging. [source]


    Search for the tumor-related proteins of transition cell carcinoma in Taiwan by proteomic analysis

    PROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 3 2006
    Kun-Hung Sheng
    Abstract To better understand the carcinogenesis of bladder cancer in Taiwan, we utilized the proteomic approach to search for potential biomarkers of transitional cell carcinoma,(TCC). Analysis by 2-DE and MS/MS indicated that seven proteins are down-regulated and three proteins up-regulated in grade III samples as compared with those of grade,II. Of these deregulated proteins, fatty acid binding proteins, annexin,V, heat-shock protein,27, and lactate dehydrogenase have been shown to be associated with bladder cancer. Our studies also found altered expression of a group of proteins that have not been documented previously in bladder cancer, including annexin,I, 15-hydroxyprostaglandin dehydrogenase, galectin-1, lysophospholipase and mitochondrial short-chain enoyl-coenzyme,A hydratase,1 precursor. These results illustrate a pattern of differential protein expression between low- and high-grade tumors and it may be utilized as the molecular fingerprinting of a subset of bladder cancers. In addition, the present study provides a valuable resource in the study of pathological mechanisms in cancers of urothelial origin. The immunohistochemical staining of grade,II and III TCC samples with antiserum to annexin,I protein was utilized to confirm that the annexin,I protein is up-regulated in grade,III TCC. [source]


    Immunohistochemical Study of HLA-G Expression in Lung Transplant Recipients

    AMERICAN JOURNAL OF TRANSPLANTATION, Issue 6 2009
    O Brugière
    Human leukocyte antigen-G (HLA-G), a nonclassical HLA class I protein, promotes immune tolerance of solid-organ allografts, yet its role in lung transplantation (LTx) is unknown. We examined the expression of HLA-G in lung allografts through immunohistochemistry by a cross-sectional study of 64 LTx recipients, classified into four groups (stable patients, acute rejection [AR], bronchiolitis obliterans syndrome [BOS] and symptomatic viral shedders). A marked expression of HLA-G in bronchial epithelial cells (BEC) was frequently observed in stable recipients (n = 18/35 [51%]), but not in patients with AR (n = 14) or with BOS (n = 8). HLA-G was also expressed by 4 of 7 symptomatic viral shedders. In addition, HLA-G-positive patients from the stable group (n = 35) experienced lower incidence of resistant AR and/or BOS during long-term follow-up, as compared with their HLA-G-negative counterparts. Finally, in vitro data showed that interferon-,, a cytokine present in lung allograft microenvironment, upregulated HLA-G mRNA and protein expression in primary cultured human BEC. We conclude that HLA-G expression in the bronchial epithelium of lung allograft is elevated in some LTx recipients in association with their functional stability, suggesting a potential role of HLA-G as a tolerance marker. [source]


    CPT-11 May Provide Therapeutic Efficacy for Esophageal Squamous Cell Cancer and the Effects Correlate with the Level of DNA Topoisomerase I Protein

    CANCER SCIENCE, Issue 12 2001
    Yasuaki Nakajima
    CPT-11 is a potent anti-cancer drug and a specific inhibitor of DNA topoisomerase I (Topo I). In this study, we aim to evaluate the effects of CPT-11 on esophageal squamous cell cancers (ESCC) and to determine the correlation between the effects and the levels of Topo I expression. We examined the growth-inhibitory effect caused by SN-38, an active metabolite of CPT-11, in 14 human ESCC cell lines established from 10 primary and 4 metastatic lesions. CPT-11 was considered effective against 5 cell lines from primary lesions and one from metastatic lesions, and thus may show therapeutic efficacy against both primary and metastatic ESCC tumors. Although Topo I mRNA levels in these 14 ESCC cell lines, as quantitated by northern blot analysis, showed no correlation with the IC50 values, Topo I protein levels, as quantitated by western blot analysis, showed an inverse correlation with the IC50 values. Topo I protein levels could be an indicator of sensitivity to CPT-11. We also determined Topo I protein levels in 40 ESCC tumors and matched normal mucosae. Thirty-four tumors showed 1.2-22.3-fold increases in Topo I levels. Two patients receiving pre-operative chemotherapy and one receiving radiotherapy exhibited increased Topo I protein levels in their tumor lesions. It appeared that CPT-11 could provide selective therapeutic efficacy against ESCC tumors. CPT-11 may be effective for the treatment of metastatic ESCC tumors and as a second-line anti-cancer drug for ESCC. [source]


    Biological function of the soluble CEACAM1 protein and implications in TAP2-deficient patients

    EUROPEAN JOURNAL OF IMMUNOLOGY, Issue 8 2004
    Gal Markel
    Abstract Interactions of natural killer (NK) cells with MHC class I proteins provide the main inhibitory signals controlling NK killing activity. It is therefore surprising to learn that TAP2-deficientpatients suffer from autoimmune manifestations only occasionally in later stages of life. We have previously described that the CEACAM1-mediated inhibitory mechanism of NK cytotoxicity plays a major role in controlling NK autoreactivity in three newly identified TAP2-deficient siblings. This novel mechanism probably compensates for the lack of MHC class I-mediated inhibition. The CEACAM1 protein can also be present in a soluble form and the biological function of the soluble form of CEACAM1 with regard to NK cells has not been investigated. Here we show that the homophilic CEACAM1 interactions are abrogated in the presence of soluble CEACAM1 protein in a dose-dependent manner. Importantly, the amounts of soluble CEACAM1 protein detected in sera derived from the TAP2-deficient patients were dramatically reduced as compared to healthy controls. This dramatic reduction does not depend on the membrane-bound metalloproteinase activity. Thus, the expression of CEACAM1 and the absence of soluble CEACAM1 observed in the TAP2-deficient patients practically maximize the inhibitory effect and probably help to minimize autoimmunity in these patients. [source]


    Allelic variants of granule-bound starch synthase proteins in European bread wheat varieties

    PLANT BREEDING, Issue 4 2000
    C. Marcoz-Ragot
    Abstract The composition of 324 European wheat cultivars were analysed at the three granule-bound starch synthase (GBSS I) loci. Protein separation was first made by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE. A specific two-dimensional (2D) electrophoresis (immobilized pH gradient × SDS-PAGE) using an Immobiline dry strip in the first dimension was developed to resolve the GBSS I proteins more clearly and to confirm some results. Very low polymorphism was found. Among the 324 cultivars analysed, only one carried a Wx-A1 null allele (Wx-A1b) and none was found to have the Wx-2D null allele. As described in the literature the Wx-B1 locus was more polymorphic and the null allele was encountered in 11 cultivars. The use of 2D electrophoresis allowed us to find another type of variant which presented as having thicker band with same mobility as the Wx-D1 protein in SDS-PAGE. Twelve per cent of the cultivars analysed presented this band and could have been previously mistaken for cultivars carrying the Wx-B1 null allele. Indeed this band probably corresponded to the Wx-B1, or Wx-B1e allele overlapping with the Wx-D1a allele in SDS-PAGE. [source]


    Age-associated decrease of CD1d protein production in normal human skin

    BRITISH JOURNAL OF DERMATOLOGY, Issue 1 2006
    M.A. Adly
    Summary Background, CD1d belongs to a family of antigen-presenting molecules structurally related to the classical major histocompatibility complex class I proteins. Objectives, To examine the expression pattern of CD1d protein in normal human skin with ageing. Methods, Twenty normal human skin biopsy specimens were obtained from 20 healthy individuals. The latter were divided into three age groups: children (5,20 years), adults (21,50 years) and the elderly (51,81 years). The intensity of CD1d protein production was examined in human skin using immunofluorescent and immunoalkalinephosphatase staining methods. Results, In the epidermis, CD1d protein production was strong in the skin of the children and declined gradually with age, being moderate in adults and weak in the elderly. As compared with values in children, there was a statistically significant decrease (P < 0·05) in CD1d protein production in the elderly. In the dermis, CD1d protein production was strong in the fibroblasts, sweat glands, sebaceous glands, blood vessels and hair follicles regardless of age. Conclusions, Our study reports a decreased CD1d protein production in normal human skin with ageing. The clinical ramifications of these observations mandate further investigations. [source]