Kooperativer Bibliotheksverbund

Berlin Brandenburg

and
and

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
Type of Medium
Language
Year
  • 1
    Language: English
    In: The Journal of biological chemistry, 23 March 2012, Vol.287(13), pp.9672-81
    Description: Stinging cells or nematocytes of jellyfish and other cnidarians represent one of the most poisonous and sophisticated cellular inventions in animal evolution. This ancient cell type is unique in containing a giant secretory vesicle derived from the Golgi apparatus. The organelle structure within the vesicle comprises an elastically stretched capsule (nematocyst) to which a long tubule is attached. During exocytosis, the barbed part of the tubule is accelerated with 〉5 million g in 〈700 ns, enabling a harpoon-like discharge (Nüchter, T., Benoit, M., Engel, U., Ozbek, S., and Holstein, T. W. (2006) Curr. Biol. 16, R316-R318). Hitherto, the molecular components responsible for the organelle's biomechanical properties were largely unknown. Here, we describe the proteome of nematocysts from the freshwater polyp Hydra magnipapillata. Our analysis revealed an unexpectedly complex secretome of 410 proteins with venomous and lytic but also adhesive or fibrous properties. In particular, the insoluble fraction of the nematocyst represents a functional extracellular matrix structure of collagenous and elastic nature. This finding suggests an evolutionary scenario in which exocytic vesicles harboring a venomous secretome assembled a sophisticated predatory structure from extracellular matrix motif proteins.
    Keywords: Evolution, Molecular ; Exocytosis -- Physiology ; Hydra -- Metabolism ; Nematocyst -- Metabolism ; Proteome -- Metabolism ; Secretory Vesicles -- Metabolism
    E-ISSN: 1083-351X
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Language: English
    In: PLoS ONE, 2011, Vol.6(7), p.e22146
    Description: MicroRNAs are 22 nucleotides long non-coding RNAs and exert their function either by transcriptional or translational inhibition. Although many microRNA profiles in different tissues and disease states have already been discovered, only little is known about their target proteins. The microRNA miR-155 is deregulated in many diseases, including cancer, where it might function as an oncoMir. ; We employed a proteomics technique called “stable isotope labelling by amino acids in cell culture” (SILAC) allowing relative quantification to reliably identify target proteins of miR-155. Using SILAC, we identified 46 putative miR-155 target proteins, some of which were previously reported. With luciferase reporter assays, CKAP5 was confirmed as a new target of miR-155. Functional annotation of miR-155 target proteins pointed to a role in cell cycle regulation. ; To the best of our knowledge we have investigated for the first time miR-155 target proteins in the HEK293T cell line in large scale. In addition, by comparing our results to previously identified miR-155 target proteins in other cell lines, we provided further evidence for the cell line specificity of microRNAs.
    Keywords: Research Article ; Biology ; Biochemistry
    E-ISSN: 1932-6203
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Language: English
    In: Analytical Biochemistry, 2011, Vol.412(1), pp.123-125
    Description: Quantitative proteomics has increasingly gained impact in life science research as a tool to describe changes in protein expression between different cellular states. Stable isotope labeling by amino acids in cell culture (SILAC) is a powerful technique for relative quantification of proteins. However, the accuracy of quantification is impaired by the metabolic conversion of arginine to proline resulting in additional heavy labeled proline peptide satellites. Here we reinvestigated the addition of unlabeled proline during cell cultivation under SILAC conditions considering several thousand peptides and demonstrated that the arginine-to-proline conversion is prevented independent of the cell line used.
    Keywords: Chemistry ; Anatomy & Physiology
    ISSN: 0003-2697
    E-ISSN: 1096-0309
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Language: English
    In: The Journal of biological chemistry, 06 January 2012, Vol.287(2), pp.1090-9
    Description: The positive transcription elongation factor b (P-TEFb) exists in two forms in cells as follows: an inactive form where the core components cyclin T1 and CDK9 are incorporated in the 7SK small nuclear ribonucleoprotein complex containing the inhibitory molecule HEXIM1, and an active form, part of which associates with the bromodomain-containing protein BRD4. Here, we define a novel interaction between P-TEFb and BRD4 involving tri-acetylated cyclin T1 (acK380, acK386, and acK309) and the second bromodomain in BRD4. This interaction is observed with the short splice variant of BRD4 (amino acids 1-722) lacking a previously defined C-terminal P-TEFb-interacting domain (PID). Notably, P-TEFb complexes associated with short BRD4 contain HEXIM1 and 7SK snRNA, implicating the PID in the liberation of P-TEFb from the 7SK small nuclear ribonucleoprotein complex (7SK snPNP). Overexpression of the PID alone in cells dissociates HEXIM1 and 7SK snRNA from P-TEFb, but it is not sufficient to activate P-TEFb-dependent transcription of the HIV LTR. Our data support a model where two BRD4 domains, the second bromodomain and the PID, bind P-TEFb and are required for full transcriptional activation of P-TEFb response genes.
    Keywords: Nuclear Proteins -- Metabolism ; Positive Transcriptional Elongation Factor B -- Metabolism ; Transcription Factors -- Metabolism ; Transcription, Genetic -- Physiology
    E-ISSN: 1083-351X
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    Language: English
    In: Science, 10 April 1992, Vol.256(5054), pp.221-225
    Description: Backbone-engineered HIV-1 protease was prepared by a total chemical synthesis approach that combines the act of joining two peptides with the generation of an analog structure. Unprotected synthetic peptide segments corresponding to the two halves of the HIV-1 protease monomer polypeptide chain were joined cleanly and in high yield through unique mutually reactive functional groups, one on each segment. Ligation was performed in 6 molar guanidine hydrochloride, thus circumventing limited solubility of protected peptide segments, the principal problem of the classical approach to the chemical synthesis of proteins. The resulting fully active HIV-1 protease analog contained a thioester replacement for the natural peptide bond between Gly$^{51}$-Gly$^{52}$ in each of the two active site flaps, a region known to be highly sensitive to mutational changes of amino acid side chains.
    Keywords: Biological sciences -- Biology -- Microbiology -- HIV ; Health sciences -- Medical treatment -- Medical procedures -- HIV ; Physical sciences -- Chemistry -- Chemical compounds -- HIV ; Physical sciences -- Chemistry -- Chemical compounds -- HIV ; Physical sciences -- Physics -- Microphysics -- HIV ; Physical sciences -- Chemistry -- Chemical bonding -- HIV ; Physical sciences -- Chemistry -- Chemical bonding -- HIV ; Physical sciences -- Physics -- Microphysics -- HIV ; Applied sciences -- Materials science -- Materials -- HIV ; Physical sciences -- Chemistry -- Chemical compounds -- HIV
    ISSN: 00368075
    E-ISSN: 10959203
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    Language: English
    In: Nucleic acids research, 17 March 2017, Vol.45(5), pp.2675-2686
    Description: SIRT7 is an NAD+-dependent protein deacetylase that regulates cell growth and proliferation. Previous studies have shown that SIRT7 is required for RNA polymerase I (Pol I) transcription and pre-rRNA processing. Here, we took a proteomic approach to identify novel molecular targets and characterize the role of SIRT7 in non-nucleolar processes. We show that SIRT7 interacts with numerous proteins involved in transcriptional regulation and RNA metabolism, the majority of interactions requiring ongoing transcription. In addition to its role in Pol I transcription, we found that SIRT7 also regulates transcription of snoRNAs and mRNAs. Mechanistically, SIRT7 promotes the release of P-TEFb from the inactive 7SK snRNP complex and deacetylates CDK9, a subunit of the elongation factor P-TEFb, which activates transcription by phosphorylating serine 2 within the C-terminal domain (CTD) of Pol II. SIRT7 counteracts GCN5-directed acetylation of lysine 48 within the catalytic domain of CDK9, deacetylation promoting CTD phosphorylation and transcription elongation.
    Keywords: Transcriptional Activation ; Cyclin-Dependent Kinase 9 -- Metabolism ; RNA Polymerase II -- Metabolism ; Sirtuins -- Metabolism
    ISSN: 03051048
    E-ISSN: 1362-4962
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    Language: English
    In: 2012, Vol.7(9), p.e45682
    Description: Tardigrades have fascinated researchers for more than 300 years because of their extraordinary capability to undergo cryptobiosis and survive extreme environmental conditions. However, the survival mechanisms of tardigrades are still poorly understood mainly due to the absence of detailed knowledge about the proteome and genome of these organisms. Our study was intended to provide a basis for the functional characterization of expressed proteins in different states of tardigrades. High-throughput, high-accuracy proteomics in combination with a newly developed tardigrade specific protein database resulted in the identification of more than 3000 proteins in three different states: early embryonic state and adult animals in active and anhydrobiotic state. This comprehensive proteome resource includes protein families such as chaperones, antioxidants, ribosomal proteins, cytoskeletal proteins, transporters, protein channels, nutrient reservoirs, and developmental proteins. A comparative analysis of protein families in the different states was performed by calculating the exponentially modified protein abundance index which classifies proteins in major and minor components. This is the first step to analyzing the proteins involved in early embryonic development, and furthermore proteins which might play an important role in the transition into the anhydrobiotic state.
    Keywords: Research Article ; Biology ; Biochemistry
    E-ISSN: 1932-6203
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    Language: English
    In: PLoS ONE, 01 January 2015, Vol.10(6), p.e0131506
    Description: Although inactivating frameshift mutations in the Transforming growth factor beta receptor type 2 (TGFBR2) gene are considered as drivers of microsatellite unstable (MSI) colorectal tumorigenesis, consequential alterations of the downstream target proteome are not resolved completely. Applying a click-it chemistry protein labeling approach combined with mass spectrometry in a MSI colorectal cancer model cell line, we identified 21 de novo synthesized proteins differentially expressed upon reconstituted TGFBR2 expression. One candidate gene, the TGF-ß family member Growth differentiation factor-15 (GDF-15), exhibited TGFBR2-dependent transcriptional upregulation causing increased intracellular and extracellular protein levels. As a new TGFBR2 target gene it may provide a link between the TGF-ß branch and the BMP/GDF branch of SMAD-mediated signaling.
    Keywords: Sciences (General)
    E-ISSN: 1932-6203
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    Language: English
    In: BBA - General Subjects, August 2013, Vol.1830(8), pp.4073-4090
    Description: Peroxiredoxins are important heterogeneous thiol-dependent hydroperoxidases with a variety of isoforms and enzymatic mechanisms. A special subclass of glutaredoxin/glutathione-dependent peroxiredoxins has been discovered in bacteria and eukaryotes during the last decade, but the exact enzymatic mechanisms of these enzymes remain to be unraveled. We performed a comprehensive analysis of the enzyme kinetics and redox states of one of these glutaredoxin/glutathione-dependent peroxiredoxins, the antioxidant protein from the malaria parasite , using steady-state kinetic measurements, site-directed mutagenesis, redox mobility shift assays, gel filtration, and mass spectrometry. antioxidant protein requires not only glutaredoxin but also glutathione as a true substrate for the reduction of hydroperoxides. One peroxiredoxin cysteine residue and one glutaredoxin cysteine residue are sufficient for catalysis, however, additional cysteine residues of both proteins result in alternative redox states and conformations with implications for redox regulation. Our data furthermore point to a glutathione-dependent peroxiredoxin activation and a negative subunit cooperativity. The investigated glutaredoxin/glutathione/peroxiredoxin system provides numerous new insights into the mechanism and redox regulation of peroxiredoxins. As a member of the special subclass of glutaredoxin/glutathione-dependent peroxiredoxins, the antioxidant protein could become a reference protein for peroxiredoxin catalysis and regulation.
    Keywords: Peroxiredoxin ; Glutathione ; Glutaredoxin ; Catalytic Mechanism ; Redox Regulation ; Malaria ; Biology ; Chemistry
    ISSN: 0304-4165
    E-ISSN: 1872-8006
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    Language: English
    In: The Journal of biological chemistry, 28 February 2014, Vol.289(9), pp.6236-47
    Description: The R2TP is a recently identified Hsp90 co-chaperone, composed of four proteins as follows: Pih1D1, RPAP3, and the AAA(+)-ATPases RUVBL1 and RUVBL2. In mammals, the R2TP is involved in the biogenesis of cellular machineries such as RNA polymerases, small nucleolar ribonucleoparticles and phosphatidylinositol 3-kinase-related kinases. Here, we characterize the spaghetti (spag) gene of Drosophila, the homolog of human RPAP3. This gene plays an essential function during Drosophila development. We show that Spag protein binds Drosophila orthologs of R2TP components and Hsp90, like its yeast counterpart. Unexpectedly, Spag also interacts and stimulates the chaperone activity of Hsp70. Using null mutants and flies with inducible RNAi, we show that spaghetti is necessary for the stabilization of snoRNP core proteins and target of rapamycin activity and likely the assembly of RNA polymerase II. This work highlights the strong conservation of both the HSP90/R2TP system and its clients and further shows that Spag, unlike Saccharomyces cerevisiae Tah1, performs essential functions in metazoans. Interaction of Spag with both Hsp70 and Hsp90 suggests a model whereby R2TP would accompany clients from Hsp70 to Hsp90 to facilitate their assembly into macromolecular complexes.
    Keywords: Hsp70 ; Hsp90 ; Protein Assembly ; R2tp Complex ; RNA Polymerase II ; Rpap3 ; Small Nucleolar RNA (Snorna) ; Spaghetti Gene ; Tor Complex (Torc) ; Models, Biological ; Drosophila Proteins -- Metabolism ; Hsp70 Heat-Shock Proteins -- Metabolism ; Heat-Shock Proteins -- Metabolism ; Molecular Chaperones -- Metabolism ; Ribonucleoproteins, Small Nucleolar -- Metabolism
    E-ISSN: 1083-351X
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. Further information can be found on the KOBV privacy pages