TY - JOUR A1 - Li, Ying H. A1 - Liu, Xianhui A1 - Vanselow, Jens T. A1 - Zheng, Haiyan A1 - Schlosser, Andreas A1 - Chiu, Joanna C. T1 - O-GlcNAcylation of PERIOD regulates its interaction with CLOCK and timing of circadian transcriptional repression JF - PLoS Genetics N2 - Circadian clocks coordinate time-of-day-specific metabolic and physiological processes to maximize organismal performance and fitness. In addition to light and temperature, which are regarded as strong zeitgebers for circadian clock entrainment, metabolic input has now emerged as an important signal for clock entrainment and modulation. Circadian clock proteins have been identified to be substrates of O-GlcNAcylation, a nutrient sensitive post-translational modification (PTM), and the interplay between clock protein O-GlcNAcylation and other PTMs is now recognized as an important mechanism by which metabolic input regulates circadian physiology. To better understand the role of O-GlcNAcylation in modulating clock protein function within the molecular oscillator, we used mass spectrometry proteomics to identify O-GlcNAcylation sites of PERIOD (PER), a repressor of the circadian transcriptome and a critical biochemical timer of the Drosophila clock. In vivo functional characterization of PER O-GlcNAcylation sites indicates that O-GlcNAcylation at PER(S942) reduces interactions between PER and CLOCK (CLK), the key transcriptional activator of clock-controlled genes. Since we observe a correlation between clock-controlled daytime feeding activity and higher level of PER O-GlcNAcylation, we propose that PER(S942) O-GlcNAcylation during the day functions to prevent premature initiation of circadian repression phase. This is consistent with the period-shortening behavioral phenotype of per(S942A) flies. Taken together, our results support that clock-controlled feeding activity provides metabolic signals to reinforce light entrainment to regulate circadian physiology at the post-translational level. The interplay between O-GlcNAcylation and other PTMs to regulate circadian physiology is expected to be complex and extensive, and reach far beyond the molecular oscillator. Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-236826 VL - 15 ER - TY - JOUR A1 - Toepfer, Franziska A1 - Wolf, Reinhard A1 - Heisenberg, Martin T1 - Multi-stability with ambiguous visual stimuli in Drosophila orientation behavior JF - PLoS Biology N2 - It is widely accepted for humans and higher animals that vision is an active process in which the organism interprets the stimulus. To find out whether this also holds for lower animals, we designed an ambiguous motion stimulus, which serves as something like a multi-stable perception paradigm in Drosophila behavior. Confronted with a uniform panoramic texture in a closed-loop situation in stationary flight, the flies adjust their yaw torque to stabilize their virtual self-rotation. To make the visual input ambiguous, we added a second texture. Both textures got a rotatory bias to move into opposite directions at a constant relative angular velocity. The results indicate that the fly now had three possible frames of reference for self-rotation: either of the two motion components as well as the integrated motion vector of the two. In this ambiguous stimulus situation, the flies generated a continuous sequence of behaviors, each one adjusted to one or another of the three references. Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-228976 VL - 16 ER - TY - JOUR A1 - Moreno-Yruela, Carlos A1 - Bæk, Michael A1 - Vrsanova, Adela-Eugenie A1 - Schulte, Clemens A1 - Maric, Hans M. A1 - Olsen, Christian A. T1 - Hydroxamic acid-modified peptide microarrays for profiling isozyme-selective interactions and inhibition of histone deacetylases JF - Nature Communications N2 - Histones control gene expression by regulating chromatin structure and function. The posttranslational modifications (PTMs) on the side chains of histones form the epigenetic landscape, which is tightly controlled by epigenetic modulator enzymes and further recognized by so-called reader domains. Histone microarrays have been widely applied to investigate histone–reader interactions, but not the transient interactions of Zn2+-dependent histone deacetylase (HDAC) eraser enzymes. Here, we synthesize hydroxamic acid-modified histone peptides and use them in femtomolar microarrays for the direct capture and detection of the four class I HDAC isozymes. Follow-up functional assays in solution provide insights into their suitability to discover HDAC substrates and inhibitors with nanomolar potency and activity in cellular assays. We conclude that similar hydroxamic acid-modified histone peptide microarrays and libraries could find broad application to identify class I HDAC isozyme-specific substrates and facilitate the development of isozyme-selective HDAC inhibitors and probes. Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-371052 VL - 12 ER - TY - JOUR A1 - Marcu, Ana A1 - Schlosser, Andreas A1 - Keupp, Anne A1 - Trautwein, Nico A1 - Johann, Pascal A1 - Wölfl, Matthias A1 - Lager, Johanna A1 - Monoranu, Camelia Maria A1 - Walz, Juliane S A1 - Henkel, Lisa M A1 - Krauß, Jürgen A1 - Ebinger, Martin A1 - Schuhmann, Martin A1 - Thomale, Ulrich Wilhelm A1 - Pietsch, Torsten A1 - Klinker, Erdwine A1 - Schlegel, Paul G A1 - Oyen, Florian A1 - Reisner, Yair A1 - Rammensee, Hans-Georg A1 - Eyrich, Matthias T1 - Natural and cryptic peptides dominate the immunopeptidome of atypical teratoid rhabdoid tumors JF - Journal for ImmunoTherapy of Cancer N2 - Background Atypical teratoid/rhabdoid tumors (AT/RT) are highly aggressive CNS tumors of infancy and early childhood. Hallmark is the surprisingly simple genome with inactivating mutations or deletions in the SMARCB1 gene as the oncogenic driver. Nevertheless, AT/RTs are infiltrated by immune cells and even clonally expanded T cells. However, it is unclear which epitopes T cells might recognize on AT/RT cells. Methods Here, we report a comprehensive mass spectrometry (MS)-based analysis of naturally presented human leukocyte antigen (HLA) class I and class II ligands on 23 AT/RTs. MS data were validated by matching with a human proteome dataset and exclusion of peptides that are part of the human benignome. Cryptic peptide ligands were identified using Peptide-PRISM. Results Comparative HLA ligandome analysis of the HLA ligandome revealed 55 class I and 139 class II tumor-exclusive peptides. No peptide originated from the SMARCB1 region. In addition, 61 HLA class I tumor-exclusive peptide sequences derived from non-canonically translated proteins. Combination of peptides from natural and cryptic class I and class II origin gave optimal representation of tumor cell compartments. Substantial overlap existed with the cryptic immunopeptidome of glioblastomas, but no concordance was found with extracranial tumors. More than 80% of AT/RT exclusive peptides were able to successfully prime CD8+ T cells, whereas naturally occurring memory responses in AT/RT patients could only be detected for class II epitopes. Interestingly, >50% of AT/RT exclusive class II ligands were also recognized by T cells from glioblastoma patients but not from healthy donors. Conclusions These findings highlight that AT/RTs, potentially paradigmatic for other pediatric tumors with a low mutational load, present a variety of highly immunogenic HLA class I and class II peptides from canonical as well as non-canonical protein sources. Inclusion of such cryptic peptides into therapeutic vaccines would enable an optimized mapping of the tumor cell surface, thereby reducing the likelihood of immune evasion. Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-370214 VL - 9 ER - TY - JOUR A1 - Marcu, Ana A1 - Bichmann, Leon A1 - Kuchenbecker, Leon A1 - Kowalewski, Daniel Johannes A1 - Freudenmann, Lena Katharina A1 - Backert, Linus A1 - Mühlenbruch, Lena A1 - Szolek, András A1 - Lübke, Maren A1 - Wagner, Philipp A1 - Engler, Tobias A1 - Matovina, Sabine A1 - Wang, Jian A1 - Hauri-Hohl, Mathias A1 - Martin, Roland A1 - Kapolou, Konstantina A1 - Walz, Juliane Sarah A1 - Velz, Julia A1 - Moch, Holger A1 - Regli, Luca A1 - Silginer, Manuela A1 - Weller, Michael A1 - Löffler, Markus W. A1 - Erhard, Florian A1 - Schlosser, Andreas A1 - Kohlbacher, Oliver A1 - Stevanović, Stefan A1 - Rammensee, Hans-Georg A1 - Neidert, Marian Christoph T1 - HLA Ligand Atlas: a benign reference of HLA-presented peptides to improve T-cell-based cancer immunotherapy JF - Journal for ImmunoTherapy of Cancer N2 - Background The human leucocyte antigen (HLA) complex controls adaptive immunity by presenting defined fractions of the intracellular and extracellular protein content to immune cells. Understanding the benign HLA ligand repertoire is a prerequisite to define safe T-cell-based immunotherapies against cancer. Due to the poor availability of benign tissues, if available, normal tissue adjacent to the tumor has been used as a benign surrogate when defining tumor-associated antigens. However, this comparison has proven to be insufficient and even resulted in lethal outcomes. In order to match the tumor immunopeptidome with an equivalent counterpart, we created the HLA Ligand Atlas, the first extensive collection of paired HLA-I and HLA-II immunopeptidomes from 227 benign human tissue samples. This dataset facilitates a balanced comparison between tumor and benign tissues on HLA ligand level. Methods Human tissue samples were obtained from 16 subjects at autopsy, five thymus samples and two ovary samples originating from living donors. HLA ligands were isolated via immunoaffinity purification and analyzed in over 1200 liquid chromatography mass spectrometry runs. Experimentally and computationally reproducible protocols were employed for data acquisition and processing. Results The initial release covers 51 HLA-I and 86 HLA-II allotypes presenting 90,428 HLA-I- and 142,625 HLA-II ligands. The HLA allotypes are representative for the world population. We observe that immunopeptidomes differ considerably between tissues and individuals on source protein and HLA-ligand level. Moreover, we discover 1407 HLA-I ligands from non-canonical genomic regions. Such peptides were previously described in tumors, peripheral blood mononuclear cells (PBMCs), healthy lung tissues and cell lines. In a case study in glioblastoma, we show that potential on-target off-tumor adverse events in immunotherapy can be avoided by comparing tumor immunopeptidomes to the provided multi-tissue reference. Conclusion Given that T-cell-based immunotherapies, such as CAR-T cells, affinity-enhanced T cell transfer, cancer vaccines and immune checkpoint inhibition, have significant side effects, the HLA Ligand Atlas is the first step toward defining tumor-associated targets with an improved safety profile. The resource provides insights into basic and applied immune-associated questions in the context of cancer immunotherapy, infection, transplantation, allergy and autoimmunity. It is publicly available and can be browsed in an easy-to-use web interface at https://hla-ligand-atlas.org . Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-370160 VL - 9 ER - TY - JOUR A1 - Loza-Valdes, Angel A1 - Mayer, Alexander E A1 - Kassouf, Toufic A1 - Trujillo-Viera, Jonathan A1 - Schmitz, Werner A1 - Dziaczkowski, Filip A1 - Leitges, Michael A1 - Schlosser, Andreas A1 - Sumara, Grzegorz T1 - A phosphoproteomic approach reveals that PKD3 controls PKA-mediated glucose and tyrosine metabolism JF - Life Science Alliance N2 - Members of the protein kinase D (PKD) family (PKD1, 2, and 3) integrate hormonal and nutritional inputs to regulate complex cellular metabolism. Despite the fact that a number of functions have been annotated to particular PKDs, their molecular targets are relatively poorly explored. PKD3 promotes insulin sensitivity and suppresses lipogenesis in the liver of animals fed a high-fat diet. However, its substrates are largely unknown. Here we applied proteomic approaches to determine PKD3 targets. We identified more than 300 putative targets of PKD3. Furthermore, biochemical analysis revealed that PKD3 regulates cAMP-dependent PKA activity, a master regulator of the hepatic response to glucagon and fasting. PKA regulates glucose, lipid, and amino acid metabolism in the liver, by targeting key enzymes in the respective processes. Among them the PKA targets phenylalanine hydroxylase (PAH) catalyzes the conversion of phenylalanine to tyrosine. Consistently, we showed that PKD3 is activated by glucagon and promotes glucose and tyrosine levels in hepatocytes. Therefore, our data indicate that PKD3 might play a role in the hepatic response to glucagon. Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-369560 VL - 4 ER - TY - JOUR A1 - Giles, James A. A1 - Greenhalgh, Andrew D. A1 - Denes, Adam A1 - Nieswandt, Bernhard A1 - Coutts, Graham A1 - McColl, Barry W. A1 - Allan, Stuart M. T1 - Neutrophil infiltration to the brain is platelet-dependent, and is reversed by blockade of platelet GPIbα JF - Immunology N2 - Neutrophils are key components of the innate immune response, providing host defence against infection and being recruited to non-microbial injury sites. Platelets act as a trigger for neutrophil extravasation to inflammatory sites but mechanisms and tissue-specific aspects of these interactions are currently unclear. Here, we use bacterial endotoxin in mice to trigger an innate inflammatory response in different tissues and measure neutrophil invasion with or without platelet reduction. We show that platelets are essential for neutrophil infiltration to the brain, peritoneum and skin. Neutrophil numbers do not rise above basal levels in the peritoneum and skin and are decreased (~60%) in the brain when platelet numbers are reduced. In contrast neutrophil infiltration in the lung is unaffected by platelet reduction, up-regulation of CXCL-1 (2·4-fold) and CCL5 (1·4-fold) acting as a compensatory mechanism in platelet-reduced mice during lung inflammation. In brain inflammation targeting platelet receptor GPIbα results in a significant decrease (44%) in platelet-mediated neutrophil invasion, while maintaining platelet numbers in the circulation. These results suggest that therapeutic blockade of platelet GPIbα could limit the harmful effects of excessive inflammation while minimizing haemorrhagic complications of platelet reduction in the brain. The data also demonstrate the ability to target damaging brain inflammation in stroke and related disorders without compromising lung immunity and hence risk of pneumonia, a major complication post stroke. In summary, our data reveal an important role for platelets in neutrophil infiltration to various tissues, including the brain, and so implicate platelets as a key, targetable component of cerebrovascular inflammatory disease or injury. KW - brain KW - inflammation KW - neuroinflammation Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-233048 VL - 154 ER - TY - JOUR A1 - Angay, Oguzhan A1 - Friedrich, Mike A1 - Pinnecker, Jürgen A1 - Hintzsche, Henning A1 - Stopper, Helga A1 - Hempel, Klaus A1 - Heinze, Katrin G. T1 - Image-based modeling and scoring of Howell–Jolly Bodies in human erythrocytes JF - Cytometry Part A N2 - The spleen selectively removes cells with intracellular inclusions, for example, detached nuclear fragments in circulating erythrocytes, called Howell–Jolly Bodies (HJBs). With absent or deficient splenic function HJBs appear in the peripheral blood and can be used as a simple and non-invasive risk-indicator for fulminant potentially life-threatening infection after spleenectomy. However, it is still under debate whether counting of the rare HJBs is a reliable measure of splenic function. Investigating HJBs in premature erythrocytes from patients during radioiodine therapy gives about 10 thousand times higher HJB counts than in blood smears. However, we show that there is still the risk of false-positive results by unspecific nuclear remnants in the prepared samples that do not originate from HJBs, but from cell debris residing above or below the cell. Therefore, we present a method to improve accuracy of image-based tests that can be performed even in non-specialized medical institutions. We show how to selectively label HJB-like clusters in human blood samples and how to only count those that are undoubtedly inside the cell. We found a “critical distance” dcrit referring to a relative HJB-Cell distance that true HJBs do not exceed. To rule out false-positive counts we present a simple inside-outside-rule based on dcrit—a robust threshold that can be easily assessed by combining conventional 2D imaging and straight-forward image analysis. Besides data based on fluorescence imaging, simulations of randomly distributed HJB-like objects on realistically modelled cell objects demonstrate the risk and impact of biased counting in conventional analysis. © 2017 The Authors. Cytometry Part A published by Wiley Periodicals, Inc. on behalf of ISAC. KW - fluorescence imaging KW - splenic function KW - Jolly bodies KW - image analysis Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-221140 VL - 93 ER - TY - JOUR A1 - Chen, Dan A1 - Gehringer, Matthias A1 - Lorenz, Sonja T1 - Developing Small-Molecule Inhibitors of HECT-Type Ubiquitin Ligases for Therapeutic Applications: Challenges and Opportunities JF - ChemBioChem N2 - The ubiquitin system regulates countless physiological and disease-associated processes and has emerged as an attractive entryway for therapeutic efforts. With over 600 members in the human proteome, ubiquitin ligases are the most diverse class of ubiquitylation enzymes and pivotal in encoding specificity in ubiquitin signaling. Although considerable progress has been made in the identification of small molecules targeting RING ligases, relatively little is known about the “druggability” of HECT (homologous to E6AP C terminus) ligases, many of which are critically implicated in human pathologies. A major obstacle to optimizing the few available ligands is our incomplete understanding of their inhibitory mechanisms and the structural basis of catalysis in HECT ligases. Here, we survey recent approaches to manipulate the activities of HECT ligases with small molecules to showcase the particular challenges and opportunities these enzymes hold as therapeutic targets. KW - drug discovery KW - enzymes KW - inhibitors KW - reaction mechanisms KW - structure-activity relationships KW - ubiquitin Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-222412 VL - 19 ER - TY - JOUR A1 - Baluapuri, Apoorva A1 - Hofstetter, Julia A1 - Dudvarski Stankovic, Nevenka A1 - Endres, Theresa A1 - Bhandare, Pranjali A1 - Vos, Seychelle Monique A1 - Adhikari, Bikash A1 - Schwarz, Jessica Denise A1 - Narain, Ashwin A1 - Vogt, Markus A1 - Wang, Shuang-Yan A1 - Düster, Robert A1 - Jung, Lisa Anna A1 - Vanselow, Jens Thorsten A1 - Wiegering, Armin A1 - Geyer, Matthias A1 - Maric, Hans Michael A1 - Gallant, Peter A1 - Walz, Susanne A1 - Schlosser, Andreas A1 - Cramer, Patrick A1 - Eilers, Martin A1 - Wolf, Elmar T1 - MYC Recruits SPT5 to RNA Polymerase II to Promote Processive Transcription Elongation JF - Molecular Cell N2 - The MYC oncoprotein binds to promoter-proximal regions of virtually all transcribed genes and enhances RNA polymerase II (Pol II) function, but its precise mode of action is poorly understood. Using mass spectrometry of both MYC and Pol II complexes, we show here that MYC controls the assembly of Pol II with a small set of transcription elongation factors that includes SPT5, a subunit of the elongation factor DSIF. MYC directly binds SPT5, recruits SPT5 to promoters, and enables the CDK7-dependent transfer of SPT5 onto Pol II. Consistent with known functions of SPT5, MYC is required for fast and processive transcription elongation. Intriguingly, the high levels of MYC that are expressed in tumors sequester SPT5 into non-functional complexes, thereby decreasing the expression of growth-suppressive genes. Altogether, these results argue that MYC controls the productive assembly of processive Pol II elongation complexes and provide insight into how oncogenic levels of MYC permit uncontrolled cellular growth. KW - MYC KW - SPT5 KW - SUPT5H KW - SPT6 KW - RNA polymerase II KW - transcription KW - elongation rate KW - processivity KW - directionality KW - tumorigenesis Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-221438 VL - 74 ER -