TY - JOUR A1 - Young, Joanna C. A1 - Clements, Abigail A1 - Lang, Alexander E. A1 - Garnett, James A. A1 - Munera, Diana A1 - Arbeloa, Ana A1 - Pearson, Jaclyn A1 - Hartland, Elizabeth L. A1 - Matthews, Stephen J. A1 - Mousnier, Aurelie A1 - Barry, David J. A1 - Way, Michael A1 - Schlosser, Andreas A1 - Aktories, Klaus A1 - Frankel, Gad T1 - The Escherichia coli effector EspJ blocks Src kinase activity via amidation and ADP ribosylation JF - Nature Communications N2 - The hallmark of enteropathogenic Escherichia coli (EPEC) infection is the formation of actin-rich pedestal-like structures, which are generated following phosphorylation of the bacterial effector Tir by cellular Src and Abl family tyrosine kinases. This leads to recruitment of the Nck-WIP-N-WASP complex that triggers Arp2/3-dependent actin polymerization in the host cell. The same phosphorylation-mediated signalling network is also assembled downstream of the Vaccinia virus protein A36 and the phagocytic Fc-gamma receptor FcγRIIa. Here we report that the EPEC type-III secretion system effector EspJ inhibits autophosphorylation of Src and phosphorylation of the Src substrates Tir and FcγRIIa. Consistent with this, EspJ inhibits actin polymerization downstream of EPEC, Vaccinia virus and opsonized red blood cells. We identify EspJ as a unique adenosine diphosphate (ADP) ribosyltransferase that directly inhibits Src kinase by simultaneous amidation and ADP ribosylation of the conserved kinase-domain residue, Src E310, resulting in glutamine-ADP ribose. Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-121157 VL - 5 IS - 5887 ER - TY - JOUR A1 - Piteau, Marianne A1 - Papatheodorou, Panagiotis A1 - Schwan, Carsten A1 - Schlosser, Andreas A1 - Aktories, Klaus A1 - Schmidt, Gudula T1 - Lu/BCAM Adhesion Glycoprotein Is a Receptor for Escherichia coli Cytotoxic Necrotizing Factor 1 (CNF1) JF - PLoS Pathogens N2 - The Cytotoxic Necrotizing Factor 1 (CNF1) is a protein toxin which is a major virulence factor of pathogenic Escherichia coli strains. Here, we identified the Lutheran (Lu) adhesion glycoprotein/basal cell adhesion molecule (BCAM) as cellular receptor for CNF1 by co-precipitation of cell surface molecules with tagged toxin. The CNF1-Lu/BCAM interaction was verified by direct protein-protein interaction analysis and competition studies. These studies revealed amino acids 720 to 1014 of CNF1 as the binding site for Lu/BCAM. We suggest two cell interaction sites in CNF1: first the N-terminus, which binds to p37LRP as postulated before. Binding of CNF1 to p37LRP seems to be crucial for the toxin's action. However, it is not sufficient for the binding of CNF1 to the cell surface. A region directly adjacent to the catalytic domain is a high affinity interaction site for Lu/BCAM. We found Lu/BCAM to be essential for the binding of CNF1 to cells. Cells deficient in Lu/BCAM but expressing p37LRP could not bind labeled CNF1. Therefore, we conclude that LRP and Lu/BCAM are both required for toxin action but with different functions. Author Summary We study a crucial virulence factor produced by pathogenic Escherichia coli strains, the Cytotoxic Necrotizing Factor 1 (CNF1). More than 80% of urinary tract infections (UTIs), which are counted among the most common bacterial infections of humans, are caused by Uropathogenic Escherichia coli (UPEC) strains. We and others elucidated the molecular mechanism of the E. coli toxin CNF1. It constitutively activates Rho GTPases by a direct covalent modification. The toxin enters mammalian cells by receptor-mediated endocytosis. Here, we identified the protein receptor for CNF1 by co-precipitation of cell surface molecules with the tagged toxin and subsequent Maldi-TOF analysis. We identified the Lutheran (Lu) adhesion glycoprotein/basal cell adhesion molecule (BCAM) as receptor for CNF1 and located its interaction site to the C-terminal part of the toxin. We performed direct protein-protein interaction analysis and competition studies. Moreover, cells deficient in Lu/BCAM could not bind labeled CNF1. The identification of a toxin's cellular receptor and receptor binding region is an important task for understanding the pathogenic function of the toxin and, moreover, to make the toxin accessible for its use as a cellbiological and pharmacological tool, for example for the generation of immunotoxins. KW - laminin receptor KW - factor-I KW - toxin KW - RHO KW - cells KW - activation KW - protein KW - domain KW - translocation KW - membrane Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-117987 SN - 1553-7374 VL - 10 IS - 1 ER - TY - JOUR A1 - Fagan, Jeremy K. A1 - Dollar, Gretchen A1 - Lu, Qiuheng A1 - Barnett, Austen A1 - Jorge, Joaquin Pechuan A1 - Schlosser, Andreas A1 - Pfleger, Cathie A1 - Adler, Paul A1 - Jenny, Andreas T1 - Combover/CG10732, a Novel PCP Effector for Drosophila Wing Hair Formation JF - PLOS ONE N2 - The polarization of cells is essential for the proper functioning of most organs. Planar Cell Polarity (PCP), the polarization within the plane of an epithelium, is perpendicular to apical-basal polarity and established by the non-canonical Wnt/Fz-PCP signaling pathway. Within each tissue, downstream PCP effectors link the signal to tissue specific readouts such as stereocilia orientation in the inner ear and hair follicle orientation in vertebrates or the polarization of ommatidia and wing hairs in Drosophila melanogaster. Specific PCP effectors in the wing such as Multiple wing hairs (Mwh) and Rho Kinase (Rok) are required to position the hair at the correct position and to prevent ectopic actin hairs. In a genome-wide screen in vitro, we identified Combover (Cmb)/CG10732 as a novel Rho kinase substrate. Overexpression of Cmb causes the formation of a multiple hair cell phenotype (MHC), similar to loss of rok and mwh. This MHC phenotype is dominantly enhanced by removal of rok or of other members of the PCP effector gene family. Furthermore, we show that Cmb physically interacts with Mwh, and cmb null mutants suppress the MHC phenotype of mwh alleles. Our data indicate that Cmb is a novel PCP effector that promotes to wing hair formation, a function that is antagonized by Mwh. KW - planar cell polarity KW - RHO-associated kinease KW - convergent extension movements KW - ROK-alpha KW - protein KW - phosphorylation KW - actin KW - gene KW - morphogenesis KW - localization Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-115394 SN - 1932-6203 VL - 9 IS - 9 ER - TY - JOUR A1 - Siegel, T. Nicolai A1 - Vasquez, Juan-José A1 - Hon, Chung-Chau A1 - Vanselow, Jens T. A1 - Schlosser, Andreas T1 - Comparative ribosome profiling reveals extensive translational complexity in different Trypanosoma brucei life cycle stages N2 - While gene expression is a fundamental and tightly controlled cellular process that is regulated at multiple steps, the exact contribution of each step remains unknown in any organism. The absence of transcription initiation regulation for RNA polymerase II in the protozoan parasite Trypanosoma brucei greatly simplifies the task of elucidating the contribution of translation to global gene expression. Therefore, we have sequenced ribosome-protected mRNA fragments in T. brucei, permitting the genome-wide analysis of RNA translation and translational efficiency. We find that the latter varies greatly between life cycle stages of the parasite and ∼100-fold between genes, thus contributing to gene expression to a similar extent as RNA stability. The ability to map ribosome positions at sub-codon resolution revealed extensive translation from upstream open reading frames located within 5' UTRs and enabled the identification of hundreds of previously un-annotated putative coding sequences (CDSs). Evaluation of existing proteomics and genome-wide RNAi data confirmed the translation of previously un-annotated CDSs and suggested an important role for >200 of those CDSs in parasite survival, especially in the form that is infective to mammals. Overall our data show that translational control plays a prevalent and important role in different parasite life cycle stages of T. brucei. KW - Ribosom KW - Profilierung KW - Trypanosoma brucei KW - Entwicklung KW - Lebenszyklus Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-112657 ER - TY - JOUR A1 - Fritz, Melanie A1 - Vanselow, Jens A1 - Sauer, Nadja A1 - Lamer, Stephanie A1 - Goos, Carina A1 - Siegel, T. Nicolai A1 - Subota, Ines A1 - Schlosser, Andreas A1 - Carrington, Mark A1 - Kramer, Susanne T1 - Novel insights into RNP granules by employing the trypanosome's microtubule skeleton as a molecular sieve JF - Nucleic Acids Research N2 - RNP granules are ribonucleoprotein assemblies that regulate the post-transcriptional fate of mRNAs in all eukaryotes. Their exact function remains poorly understood, one reason for this is that RNP granule purification has not yet been achieved. We have exploited a unique feature of trypanosomes to prepare a cellular fraction highly enriched in starvation stress granules. First, granules remain trapped within the cage-like, subpellicular microtubule array of the trypanosome cytoskeleton while soluble proteins are washed away. Second, the microtubules are depolymerized and the granules are released. RNA sequencing combined with single molecule mRNA FISH identified the short and highly abundant mRNAs encoding ribosomal mRNAs as being excluded from granules. By mass spectrometry we have identified 463 stress granule candidate proteins. For 17/49 proteins tested by eYFP tagging we have confirmed the localization to granules, including one phosphatase, one methyltransferase and two proteins with a function in trypanosome life-cycle regulation. The novel method presented here enables the unbiased identification of novel RNP granule components, paving the way towards an understanding of RNP granule function. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-126180 ER - TY - JOUR A1 - Eisenhardt, Anja E. A1 - Sprenger, Adrian A1 - Röring, Michael A1 - Herr, Ricarda A1 - Weinberg, Florian A1 - Köhler, Martin A1 - Braun, Sandra A1 - Orth, Joachim A1 - Diedrich, Britta A1 - Lanner, Ulrike A1 - Tscherwinski, Natalja A1 - Schuster, Simon A1 - Dumaz, Nicolas A1 - Schmidt, Enrico A1 - Baumeister, Ralf A1 - Schlosser, Andreas A1 - Dengjel, Jörn A1 - Brummer, Tilman T1 - Phospho-proteomic analyses of B-Raf protein complexes reveal new regulatory principles JF - Oncotarget N2 - B-Raf represents a critical physiological regulator of the Ras/RAF/MEK/ERK-pathway and a pharmacological target of growing clinical relevance, in particular in oncology. To understand how B-Raf itself is regulated, we combined mass spectrometry with genetic approaches to map its interactome in MCF-10A cells as well as in B-Raf deficient murine embryonic fibroblasts (MEFs) and B-Raf/Raf-1 double deficient DT40 lymphoma cells complemented with wildtype or mutant B-Raf expression vectors. Using a multi-protease digestion approach, we identified a novel ubiquitination site and provide a detailed B-Raf phospho-map. Importantly, we identify two evolutionary conserved phosphorylation clusters around T401 and S419 in the B-Raf hinge region. SILAC labelling and genetic/biochemical follow-up revealed that these clusters are phosphorylated in the contexts of oncogenic Ras, sorafenib induced Raf dimerization and in the background of the V600E mutation. We further show that the vemurafenib sensitive phosphorylation of the T401 cluster occurs in trans within a Raf dimer. Substitution of the Ser/Thr-residues of this cluster by alanine residues enhances the transforming potential of B-Raf, indicating that these phosphorylation sites suppress its signaling output. Moreover, several B-Raf phosphorylation sites, including T401 and S419, are somatically mutated in tumors, further illustrating the importance of phosphorylation for the regulation of this kinase. KW - BRAF KW - proteomics KW - phosphorylation KW - sorafenib KW - protein-protein interaction Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-166529 VL - 7 IS - 18 ER - TY - JOUR A1 - Jarick, Marcel A1 - Bertsche, Ute A1 - Stahl, Mark A1 - Schultz, Daniel A1 - Methling, Karen A1 - Lalk, Michael A1 - Stigloher, Christian A1 - Steger, Mirco A1 - Schlosser, Andreas A1 - Ohlsen, Knut T1 - The serine/threonine kinase Stk and the phosphatase Stp regulate cell wall synthesis in Staphylococcus aureus JF - Scientific Reports N2 - The cell wall synthesis pathway producing peptidoglycan is a highly coordinated and tightly regulated process. Although the major components of bacterial cell walls have been known for decades, the complex regulatory network controlling peptidoglycan synthesis and many details of the cell division machinery are not well understood. The eukaryotic-like serine/threonine kinase Stk and the cognate phosphatase Stp play an important role in cell wall biosynthesis and drug resistance in S. aureus. We show that stp deletion has a pronounced impact on cell wall synthesis. Deletion of stp leads to a thicker cell wall and decreases susceptibility to lysostaphin. Stationary phase Δstp cells accumulate peptidoglycan precursors and incorporate higher amounts of incomplete muropeptides with non-glycine, monoglycine and monoalanine interpeptide bridges into the cell wall. In line with this cell wall phenotype, we demonstrate that the lipid II:glycine glycyltransferase FemX can be phosphorylated by the Ser/Thr kinase Stk in vitro. Mass spectrometric analyses identify Thr32, Thr36 and Ser415 as phosphoacceptors. The cognate phosphatase Stp dephosphorylates these phosphorylation sites. Moreover, Stk interacts with FemA and FemB, but is unable to phosphorylate them. Our data indicate that Stk and Stp modulate cell wall synthesis and cell division at several levels. KW - bacterial transcription KW - pathogens KW - cell wall synthesis Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-177333 VL - 8 IS - 13693 ER - TY - JOUR A1 - Mietrach, Nicole A1 - Schlosser, Andreas A1 - Geibel, Sebastian T1 - An extracellular domain of the EsaA membrane component of the type VIIb secretion system: expression, purification and crystallization JF - Acta Crystallographica Section F N2 - The membrane protein EsaA is a conserved component of the type VIIb secretion system. Limited proteolysis of purified EsaA from Staphylococcus aureus USA300 identified a stable 48 kDa fragment, which was mapped by fingerprint mass spectrometry to an uncharacterized extracellular segment of EsaA. Analysis by circular dichroism spectroscopy showed that this fragment folds into a single stable domain made of mostly α‐helices with a melting point of 34.5°C. Size‐exclusion chromatography combined with multi‐angle light scattering indicated the formation of a dimer of the purified extracellular domain. Octahedral crystals were grown in 0.2 M ammonium citrate tribasic pH 7.0, 16% PEG 3350 using the hanging‐drop vapor‐diffusion method. Diffraction data were analyzed to 4.0 Å resolution, showing that the crystals belonged to the enantiomorphic tetragonal space groups P41212 or P43212, with unit‐cell parameters a = 197.5, b = 197.5, c = 368.3 Å, α = β = γ = 90°. KW - ESAT‐6‐like secretion system KW - ESS KW - type VII secretion system KW - EsaA KW - extracellular domain KW - Staphylococcus aureus USA300 Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-213681 VL - 75 IS - 12 ER - TY - JOUR A1 - Pauls, Dennis A1 - Hamarat, Yasmin A1 - Trufasu, Luisa A1 - Schendzielorz, Tim M. A1 - Gramlich, Gertrud A1 - Kahnt, Jörg A1 - Vanselow, Jens A1 - Schlosser, Andreas A1 - Wegener, Christian T1 - Drosophila carboxypeptidase D (SILVER) is a key enzyme in neuropeptide processing required to maintain locomotor activity levels and survival rate JF - European Journal of Neuroscience N2 - Neuropeptides are processed from larger preproproteins by a dedicated set of enzymes. The molecular and biochemical mechanisms underlying preproprotein processing and the functional importance of processing enzymes are well‐characterised in mammals, but little studied outside this group. In contrast to mammals, Drosophila melanogaster lacks a gene for carboxypeptidase E (CPE ), a key enzyme for mammalian peptide processing. By combining peptidomics and neurogenetics, we addressed the role of carboxypeptidase D (dCPD ) in global neuropeptide processing and selected peptide‐regulated behaviours in Drosophila . We found that a deficiency in dCPD results in C‐terminally extended peptides across the peptidome, suggesting that dCPD took over CPE function in the fruit fly. dCPD is widely expressed throughout the nervous system, including peptidergic neurons in the mushroom body and neuroendocrine cells expressing adipokinetic hormone. Conditional hypomorphic mutation in the dCPD ‐encoding gene silver in the larva causes lethality, and leads to deficits in starvation‐induced hyperactivity and appetitive gustatory preference, as well as to reduced viability and activity levels in adults. A phylogenomic analysis suggests that loss of CPE is not common to insects, but only occurred in Hymenoptera and Diptera. Our results show that dCPD is a key enzyme for neuropeptide processing and peptide‐regulated behaviour in Drosophila . dCPD thus appears as a suitable target to genetically shut down total neuropeptide production in peptidergic neurons. The persistent occurrence of CPD in insect genomes may point to important further CPD functions beyond neuropeptide processing which cannot be fulfilled by CPE. KW - direct muss spectrometric profiling KW - friut fly behaviour KW - M14 carboxypeptidasses KW - peptidomoics KW - protein processing Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-204863 VL - 50 IS - 9 ER - TY - JOUR A1 - El-Mesery, Mohamed A1 - Rosenthal, Tina A1 - Rauert-Wunderlich, Hilka A1 - Schreder, Martin A1 - Stühmer, Thorsten A1 - Leich, Ellen A1 - Schlosser, Andreas A1 - Ehrenschwender, Martin A1 - Wajant, Harald A1 - Siegmund, Daniela T1 - The NEDD8-activating enzyme inhibitor MLN4924 sensitizes a TNFR1+ subgroup of multiple myeloma cells for TNF-induced cell death JF - Cell Death & Disease N2 - The NEDD8-activating enzyme (NAE) inhibitor MLN4924 inhibits cullin-RING ubiquitin ligase complexes including the SKP1-cullin-F-box E3 ligase βTrCP. MLN4924 therefore inhibits also the βTrCP-dependent activation of the classical and the alternative NFĸB pathway. In this work, we found that a subgroup of multiple myeloma cell lines (e.g., RPMI-8226, MM.1S, KMS-12BM) and about half of the primary myeloma samples tested are sensitized to TNF-induced cell death by MLN4924. This correlated with MLN4924-mediated inhibition of TNF-induced activation of the classical NFκB pathway and reduced the efficacy of TNF-induced TNFR1 signaling complex formation. Interestingly, binding studies revealed a straightforward correlation between cell surface TNFR1 expression in multiple myeloma cell lines and their sensitivity for MLN4924/TNF-induced cell death. The cell surface expression levels of TNFR1 in the investigated MM cell lines largely correlated with TNFR1 mRNA expression. This suggests that the variable levels of cell surface expression of TNFR1 in myeloma cell lines are decisive for TNF/MLN4924 sensitivity. Indeed, introduction of TNFR1 into TNFR1-negative TNF/MLN4924-resistant KMS-11BM cells, was sufficient to sensitize this cell line for TNF/MLN4924-induced cell death. Thus, MLN4924 might be especially effective in myeloma patients with TNFR1+ myeloma cells and a TNFhigh tumor microenvironment. KW - cancer therapy KW - tumour-necrosis factors Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-226666 VL - 10 ER -