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321.
Objective
Tetrameric α2-macroglobulin (α2M), a plasma panproteinase inhibitor, is activated upon interaction with a proteinase, and undergoes a major conformational change exposing a receptor recognition site in each of its subunits. Activated α2M (α2M*) binds to cancer cell surface GRP78 and triggers proliferative and antiapoptotic signaling. We have studied the role of α2M* in the regulation of mTORC1 and TORC2 signaling in the growth of human prostate cancer cells.Methods
Employing immunoprecipitation techniques and Western blotting as well as kinase assays, activation of the mTORC1 and mTORC2 complexes, as well as down stream targets were studied. RNAi was also employed to silence expression of Raptor, Rictor, or GRP78 in parallel studies.Results
Stimulation of cells with α2M* promotes phosphorylation of mTOR, TSC2, S6-Kinase, 4EBP, AktT308, and AktS473 in a concentration and time-dependent manner. Rheb, Raptor, and Rictor also increased. α2M* treatment of cells elevated mTORC1 kinase activity as determined by kinase assays of mTOR or Raptor immunoprecipitates. mTORC1 activity was sensitive to and rapamycin or transfection of cells with GRP78 dsRNA. Down regulation of Raptor expression by RNAi significantly reduced α2M*-induced S6-Kinase phosphorylation at T389 and kinase activity in Raptor immunoprecipitates. α2M*-treated cells demonstrate about a twofold increase in mTORC2 kinase activity as determined by kinase assay of AktS473 phosphorylation and levels of p-AktS473 in mTOR and Rictor immunoprecipitates. mTORC2 activity was sensitive to LY294002 and transfection of cells with GRP78 dsRNA, but insensitive to rapamycin. Down regulation of Rictor expression by RNAi significantly reduces α2M*-induced phosphorylation of AktS473 phosphorylation in Rictor immunoprecipitates. LY294002Conclusion
Binding of α2M* to prostate cancer cell surface GRP78 upregulates mTORC1 and mTORC2 activation and promotes protein synthesis in the prostate cancer cells. 相似文献322.
D Licastro M Mutarelli I Peluso K Neveling N Wieskamp R Rispoli D Vozzi E Athanasakis A D'Eustacchio M Pizzo F D'Amico C Ziviello F Simonelli A Fabretto H Scheffer P Gasparini S Banfi V Nigro 《PloS one》2012,7(8):e43799
Usher syndrome (USH) is a clinically and genetically heterogeneous disorder characterized by visual and hearing impairments. Clinically, it is subdivided into three subclasses with nine genes identified so far. In the present study, we investigated whether the currently available Next Generation Sequencing (NGS) technologies are already suitable for molecular diagnostics of USH. We analyzed a total of 12 patients, most of which were negative for previously described mutations in known USH genes upon primer extension-based microarray genotyping. We enriched the NGS template either by whole exome capture or by Long-PCR of the known USH genes. The main NGS sequencing platforms were used: SOLiD for whole exome sequencing, Illumina (Genome Analyzer II) and Roche 454 (GS FLX) for the Long-PCR sequencing. Long-PCR targeting was more efficient with up to 94% of USH gene regions displaying an overall coverage higher than 25×, whereas whole exome sequencing yielded a similar coverage for only 50% of those regions. Overall this integrated analysis led to the identification of 11 novel sequence variations in USH genes (2 homozygous and 9 heterozygous) out of 18 detected. However, at least two cases were not genetically solved. Our result highlights the current limitations in the diagnostic use of NGS for USH patients. The limit for whole exome sequencing is linked to the need of a strong coverage and to the correct interpretation of sequence variations with a non obvious, pathogenic role, whereas the targeted approach suffers from the high genetic heterogeneity of USH that may be also caused by the presence of additional causative genes yet to be identified. 相似文献
323.
Pierre Theurey Niamh M. C. Connolly Ilaria Fortunati Emy Basso Susette Lauwen Camilla Ferrante Catarina Moreira Pinho Alvin Joselin Anna Gioran Daniele Bano David S. Park Maria Ankarcrona Paola Pizzo Jochen H. M. Prehn 《Aging cell》2019,18(3)
Mitochondrial dysfunction is implicated in most neurodegenerative diseases, including Alzheimer's disease (AD). We here combined experimental and computational approaches to investigate mitochondrial health and bioenergetic function in neurons from a double transgenic animal model of AD (PS2APP/B6.152H). Experiments in primary cortical neurons demonstrated that AD neurons had reduced mitochondrial respiratory capacity. Interestingly, the computational model predicted that this mitochondrial bioenergetic phenotype could not be explained by any defect in the mitochondrial respiratory chain (RC), but could be closely resembled by a simulated impairment in the mitochondrial NADH flux. Further computational analysis predicted that such an impairment would reduce levels of mitochondrial NADH, both in the resting state and following pharmacological manipulation of the RC. To validate these predictions, we utilized fluorescence lifetime imaging microscopy (FLIM) and autofluorescence imaging and confirmed that transgenic AD neurons had reduced mitochondrial NAD(P)H levels at rest, and impaired power of mitochondrial NAD(P)H production. Of note, FLIM measurements also highlighted reduced cytosolic NAD(P)H in these cells, and extracellular acidification experiments showed an impaired glycolytic flux. The impaired glycolytic flux was identified to be responsible for the observed mitochondrial hypometabolism, since bypassing glycolysis with pyruvate restored mitochondrial health. This study highlights the benefits of a systems biology approach when investigating complex, nonintuitive molecular processes such as mitochondrial bioenergetics, and indicates that primary cortical neurons from a transgenic AD model have reduced glycolytic flux, leading to reduced cytosolic and mitochondrial NAD(P)H and reduced mitochondrial respiratory capacity. 相似文献
324.
Lucilla Pizzo Micaela Lasser Tanzeen Yusuff Matthew Jensen Phoebe Ingraham Emily Huber Mayanglambam Dhruba Singh Connor Monahan Janani Iyer Inshya Desai Siddharth Karthikeyan Dagny J. Gould Sneha Yennawar Alexis T. Weiner Vijay Kumar Pounraja Arjun Krishnan Melissa M. Rolls Laura Anne Lowery Santhosh Girirajan 《PLoS genetics》2021,17(4)
325.
Ombretta Repetto Stefania Zanussi Mariateresa Casarotto Vincenzo Canzonieri Paolo De Paoli Renato Cannizzaro Valli De Re 《Molecular medicine (Cambridge, Mass.)》2014,20(1):57-71
Atrophic autoimmune gastritis (AAG) is a condition of chronic inflammation and atrophy of stomach mucosa, for which development can be partially triggered by the bacterial pathogen Helicobacter pylori (HP). HP can cause a variety of gastric diseases, such as duodenal ulcer (DU) or gastric cancer (GC). In this study, a comparative proteomic approach was used by two-dimensional fluorescence difference gel electrophoresis (DIGE) to identify differentially expressed proteins of HP strains isolated from patients with AAG, to identify markers of HP strain associated with AAG. Proteome profiles of HP isolated from GC or DU were used as a reference to compare proteomic levels. Proteomics analyses revealed 27 differentially expressed spots in AAG-associated HP in comparison with GC, whereas only 9 differential spots were found in AAG-associated HP profiles compared with DU. Proteins were identified after matrix-assisted laser desorption ionization (MALDI)-TOF and peptide mass fingerprinting. Some AAG-HP differential proteins were common between DU- and GC-HP (peroxiredoxin, heat shock protein 70 [HSP70], adenosine 5′-triphosphate [ATP] synthase subunit α, flagellin A). Our results presented here may suggest that comparative proteomes of HP isolated from AAG and DU share more common protein expression than GC and provide subsets of putative AAG-specific upregulated or downregulated proteins that could be proposed as putative markers of AAG-associated HP. Other comparative studies by two-dimensional maps integrated with functional genomics of candidate proteins will undoubtedly contribute to better decipher the biology of AAG-associated HP strains. 相似文献
326.
Mitofusin‐2 knockdown increases ER–mitochondria contact and decreases amyloid β‐peptide production
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Nuno Santos Leal Bernadette Schreiner Catarina Moreira Pinho Riccardo Filadi Birgitta Wiehager Helena Karlström Paola Pizzo Maria Ankarcrona 《Journal of cellular and molecular medicine》2016,20(9):1686-1695
Mitochondria are physically and biochemically in contact with other organelles including the endoplasmic reticulum (ER). Such contacts are formed between mitochondria‐associated ER membranes (MAM), specialized subregions of ER, and the outer mitochondrial membrane (OMM). We have previously shown increased expression of MAM‐associated proteins and enhanced ER to mitochondria Ca2+ transfer from ER to mitochondria in Alzheimer's disease (AD) and amyloid β‐peptide (Aβ)‐related neuronal models. Here, we report that siRNA knockdown of mitofusin‐2 (Mfn2), a protein that is involved in the tethering of ER and mitochondria, leads to increased contact between the two organelles. Cells depleted in Mfn2 showed increased Ca2+ transfer from ER to mitchondria and longer stretches of ER forming contacts with OMM. Interestingly, increased contact resulted in decreased concentrations of intra‐ and extracellular Aβ40 and Aβ42. Analysis of γ‐secretase protein expression, maturation and activity revealed that the low Aβ concentrations were a result of impaired γ‐secretase complex function. Amyloid‐β precursor protein (APP), β‐site APP‐cleaving enzyme 1 and neprilysin expression as well as neprilysin activity were not affected by Mfn2 siRNA treatment. In summary, our data shows that modulation of ER–mitochondria contact affects γ‐secretase activity and Aβ generation. Increased ER–mitochondria contact results in lower γ‐secretase activity suggesting a new mechanism by which Aβ generation can be controlled. 相似文献
327.
A. Pizzo D. Mercurio C. Palestrini A. Roggero A. Rolando 《Journal of Zoological Systematics and Evolutionary Research》2006,44(1):54-62
This paper focuses on morphological (both shape and size ) differences that quite similar polyphenic sister species evolve during divergence processes. Traits were analysed using a geometrical morphometric approach, which has the ability to evidence also very subtle differences in shape. As a case study, we considered males of the dung beetle sister species pair Onthophagus taurus and Onthophagus illyricus (Coleoptera, Scarabaeidae); these species represent a typical example of polyphenic trait expression concerning the facultative development of horns and considerable body size differences. External shape morphology failed to discriminate O. taurus from O. illyricus , whereas the reproductive system shape showed significant interspecific discrimination power. However, the head of O. taurus was significantly larger than that of O. illyricus and the reverse was true for the elytra. The two species also showed different allometric values of the head with respect to body size. This complex pattern of interspecific morphological divergence is discussed in the light of the differential trait divergence rate hypothesis. In both species, differences between major and minor forms concern the overall shape of head and pronotum: we suggest that such different forms, which likely reflect morphological readjustment to accommodate horns of considerable bulk and disproportionate length, may be nevertheless advantageously used by the two male morphs in their alternative reproductive tactics. Male genitalia sizes were virtually constant with respect to body size; however, the ratio between phallotheca and body size was significantly higher in minor males, in keeping with the hypothesis of a higher investment in genitalia borne by this morph. 相似文献
328.
Alex Costa Ilaria Drago Smrutisanjita Behera Michela Zottini Paola Pizzo Julian I. Schroeder Tullio Pozzan Fiorella Lo Schiavo 《The Plant journal : for cell and molecular biology》2010,62(5):760-772
Oxidative stress is a major challenge for all cells living in an oxygen‐based world. Among reactive oxygen species, H2O2, is a well known toxic molecule and, nowadays, considered a specific component of several signalling pathways. In order to gain insight into the roles played by H2O2 in plant cells, it is necessary to have a reliable, specific and non‐invasive methodology for its in vivo detection. Hence, the genetically encoded H2O2 sensor HyPer was expressed in plant cells in different subcellular compartments such as cytoplasm and peroxisomes. Moreover, with the use of the new green fluorescent protein (GFP)‐based Cameleon Ca2+ indicator, D3cpv–KVK–SKL, targeted to peroxisomes, we demonstrated that the induction of cytoplasmic Ca2+ increase is followed by Ca2+ rise in the peroxisomal lumen. The analyses of HyPer fluorescence ratios were performed in leaf peroxisomes of tobacco and pre‐ and post‐bolting Arabidopsis plants. These analyses allowed us to demonstrate that an intraperoxisomal Ca2+ rise in vivo stimulates catalase activity, increasing peroxisomal H2O2 scavenging efficiency. 相似文献
329.
Volpicella M Cordewener J Jongsma MA Gallerani R Ceci LR Beekwilder J 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2006,833(1):26-32
Protease inhibitors mediate a natural form of plant defence against insects, by interfering with the digestive system of the insect. In this paper, affinity chromatography was used to isolate trypsins and chymotrypsins from Helicoverpa zea larvae, which had been raised on inhibitor-containing diet. Sensitivity of the fractions to inhibition by plant proteinase inhibitors was tested, and compared to the sensitivity of proteinases found in insects raised on diet to which no inhibitor had been added. The isolated chymotrypsin activity was found to be less sensitive to plant protease inhibitors. The sensitivity of the isolated trypsin activity was found to be intermediate between completely sensitive trypsins and completely insensitive forms that have been previously described. Mass spectrometry was used to identify one trypsin and two chymotrypsins in the partially purified protease fraction. The sequence features of these proteases are discussed in relation to their sensitivity to inhibitors. The results provide insight in the enzymes deployed by Helicoverpa larvae to overcome plant defence. 相似文献
330.
Pamela Crepaldi Barbara Cacciari Maria-Cruz Bonache Giampiero Spalluto Katia Varani Pier Andrea Borea Ivar von Kügelgen Kristina Hoffmann Mariateresa Pugliano Cristina Razzari Marco Cattaneo 《Bioorganic & medicinal chemistry》2009,17(13):4612-4621
P2Y12 plays an important role in platelet aggregation, which makes it an interesting target for antithrombotic agents. Compounds that antagonize P2Y12 include the active metabolites of thienopyridines and molecules that are structurally related to ATP, which is an antagonist of P2Y12. During the last few years, our group has been working on the development of P2Y12 receptors antagonists that are based on an extremely simple chemical structure, the 6-amino-2-mercapto-3H-pyrimidin-4-one, variously substituted at the sulfur and oxygen functions. This nucleus represents the simplified combination of two known P2Y12 antagonists: the active metabolite of the thienopyridines and ATP derivatives. The effects of the synthesized compounds were tested on ADP-induced human platelet aggregation, using light transmission aggregometry. None of the tested compounds induced platelet aggregation, while some of them, at concentration of 10?4 M, partially inhibited platelet aggregation induced by ADP 10?6 M. The most potent compound, 6b, antagonized the inhibitory effect of 2-methylthio-ADP on the forskolin-induced accumulation of cyclic-AMP in CHO FlpIN cells expressing recombinant human P2Y12-receptors. In addition, none of the tested compounds, including 6b, interfered with ligand binding to P1 receptors. Our results suggest that some of the synthesized compounds are specific antagonists of P2 receptors, and in particular of P2Y12 and suggest that further development of this structurally new series of compounds as P2Y12 receptors antagonists is recommended. 相似文献