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Valosin-containing Protein (valosin-containing + protein)

Distribution by Scientific Domains

Medical Sciences	50%

Selected Abstracts

Identification of plasma membrane autoantigens in autoimmune hepatitis type 1 using a proteomics tool,,

HEPATOLOGY, Issue 3 2008
Fatima Tahiri
Autoimmune hepatitis (AIH) is a liver disease with circulating autoantibodies predominantly directed against widely held cellular components. Because AIH is a liver-specific disease, autoantibodies against plasma membrane antigens may be involved in its pathogenesis and have been reported; however, no definite identification has been described. We thus investigated the fine specificity of anti-hepatocyte plasma membrane autoantibodies in type 1 AIH (AIH-1) using a proteomic tool. A plasma membrane,enriched fraction was validated using enzymatic activity and western blot analysis experiments. Sera from AIH-1 patients (n = 65) and from 90 controls, that is, healthy blood donors (n = 40) and patients with systemic diseases (n = 20) or other liver diseases (n = 30), were studied by immunoblot performed with plasma membrane proteins resolved by either sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) or 2-dimensional (2D) electrophoresis. Proteins contained in the immunoreactive spots were identified by sequences provided by ion-trap mass spectrometry. Hepatocytes probed with sera were also studied using confocal immunofluorescence and immunoelectron microscopy. The more prominent bands stained by patient sera were located at 38 kDa, 48, 50, 52 kDa, 62 kDa, 70 kDa, and a 95-kDa double band. Six proteins with known potential plasma membrane expression were identified: liver arginase (38 kDa), cytokeratins (CK) 8 and 18 (48-52 kDa), heat shock proteins (HSP) of 60, 70, 90 kDa, and valosin-containing protein (VCP) of 92 kDa. The presence of anti-membrane antibodies was confirmed by immunofluorescence and immunoelectron microscopy. Conclusion: Overall, our data demonstrate that liver arginase, CK 8/18, HSP 60, HSP 70, HSP 90, and VCP represent potential candidate targets on liver membrane for autoantibodies in AIH-1. (HEPATOLOGY 2008;47:937,948.) [source]

Unintended changes in protein expression revealed by proteomic analysis of seeds from transgenic pea expressing a bean ,-amylase inhibitor gene

PROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 18 2009
Hancai Chen
Abstract Seeds of genetically modified (GM) peas (Pisum sativum L.) expressing the gene for ,-amylase inhibitor-1 (,AI1) from the common bean (Phaseolus vulgaris L. cv. Tendergreen) exhibit resistance to the pea weevil (Bruchus pisorum). A proteomic analysis was carried out to compare seeds from GM pea lines expressing the bean ,AI1 protein and the corresponding ,AI1-free segregating lines and non-GM parental line to identify unintended alterations to the proteome of GM peas due to the introduction of the gene for ,AI1. Proteomic analysis showed that in addition to the presence of ,AI1, 33 other proteins were differentially accumulated in the ,AI1-expressing GM lines compared with their non-GM parental line and these were grouped into five expression classes. Among these 33 proteins, only three were found to be associated with the expression of ,AI1 in the GM pea lines. The accumulation of the remaining 30 proteins appears to be associated with Agrobacterium -mediated transformation events. Sixteen proteins were identified after MALDI-TOF-TOF analysis. About 56% of the identified proteins with altered accumulation in the GM pea were storage proteins including legumin, vicilin or convicilin, phaseolin, cupin and valosin-containing protein. Two proteins were uniquely expressed in the ,AI1-expressing GM lines and one new protein was present in both the ,AI1-expressing GM lines and their ,AI1-free segregating lines, suggesting that both transgenesis and transformation events led to demonstrable changes in the proteomes of the GM lines tested. [source]

Exploring the priming mechanism of liver regeneration: proteins and protein complexes

PROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 8 2009
Xinyu Deng
Abstract The liver has the ability to restore its functional capacity following injury or resection and the priming of liver regeneration is a complex process that has not been completely elucidated. In the current research, to further reveal the priming mechanism of liver regeneration, hepatocyte total protein and hepatocyte cytosol of the rats at 4,h after 2/3 partial hepatectomy (PHx) were studied, respectively, by 2-DE and 2-D blue native gel electrophoresis. Seventeen unique differential proteins were identified in hepatocyte total protein samples. Nine differential protein complexes containing 41 protein components were identified in hepatocyte cytosol samples. For the first time, at the priming stage of liver regeneration, the variations of serine protease inhibitor 2c, sulfite oxidase and valosin-containing protein (VCP) were presented and validated by Western blotting, and the VCP complex was further validated by antibody super-shift experiments. The current results suggested that at 4,h after PHx, VCP complex was down-regulated in hepatocyte cytosol, apoptosis pathways were inhibited, nuclear factor-,B and interleukin 6 pathways worked together and triggered the liver regeneration. [source]

VCP (p97) Regulates NFKB Signaling Pathway, Which Is Important for Metastasis of Osteosarcoma Cell Line

CANCER SCIENCE, Issue 3 2002
Tatsuya Asai
In order to identify genes associated with metastasis, suppression subtractive hybridization (SSH) was performed using murine osteosarcoma cell line Dunn and its subline with higher metastatic potential, LM8. SSH revealed expression of the gene encoding valosin-containing protein (VCP; also known as p97) to be constitutively activated in LM8 cells, but it declined in Dunn cells when the cells became confluent. Because VCP is known to be involved in the ubiquitination process of Inhibitor-,B, (I,B,), an inhibitor of nuclear factor-,B (NF,B), whether VCP influences NF,B activation or not was examined by using VCP-transfected Dunn cells (Dunn/VCPs). When stimulated with tumor necrosis factor-, (TNF,), Dunn/VCPs showed constantly activated NF,B, although in the original Dunn cells and control vector transfectant (Dunn/Dunn-c) NF,B activation ceased when the cells became confluent. Western immunoblot analysis showed an increase of phosphorylated I,B, (p-IKB,) in the cytoplasm of confluent Dunn/Dunn-c cells compared to that of Dunn/VCPs. Therefore, decrease of p-IKB, degrading activity might be responsible for the decrease in NFKB activation. In vitro apoptosis assay demonstrated increased apoptosis rates of Dunn/Dunn-c cells after TNF, stimulation compared to those of Dunn/VCPs and LM8 cells. In vivo metastasis assay showed increased incidences of metastatic events in Dunn/VCP-1 inoculated male C3H mice compared to those in Dunn/Dunn-c inoculated mice. These findings suggested that VCP expression plays an important role in the metastatic process. Anti-apoptotic potential in these cells owing to constant NFKB activation via efficient cytoplasmic p-IKB, degrading activity may explain the increased metastatic potential of these cells. [source]