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Teperino R.,Max Planck Institute of Immunobiology and Epigenetics | Amann S.,Medical University of Vienna | Bayer M.,Medical University of Vienna | McGee S.L.,Deakin University | And 17 more authors.
Cell | Year: 2012

Diabetes, obesity, and cancer affect upward of 15% of the world's population. Interestingly, all three diseases juxtapose dysregulated intracellular signaling with altered metabolic state. Exactly which genetic factors define stable metabolic set points in vivo remains poorly understood. Here, we show that hedgehog signaling rewires cellular metabolism. We identify a cilium-dependent Smo-Ca2+-Ampk axis that triggers rapid Warburg-like metabolic reprogramming within minutes of activation and is required for proper metabolic selectivity and flexibility. We show that Smo modulators can uncouple the Smo-Ampk axis from canonical signaling and identify cyclopamine as one of a new class of "selective partial agonists," capable of concomitant inhibition of canonical and activation of noncanonical hedgehog signaling. Intriguingly, activation of the Smo-Ampk axis in vivo drives robust insulin-independent glucose uptake in muscle and brown adipose tissue. These data identify multiple noncanonical endpoints that are pivotal for rational design of hedgehog modulators and provide a new therapeutic avenue for obesity and diabetes. © 2012 Elsevier Inc. Source

Sobrero P.,National University of Quilmes | Schluter J.-P.,Albert Ludwigs University of Freiburg | Schluter J.-P.,Center for Synthetic Microbiology | Lanner U.,Center for Biological Systems Analysis | And 5 more authors.
PLoS ONE | Year: 2012

Riboregulation stands for RNA-based control of gene expression. In bacteria, small non-coding RNAs (sRNAs) are a major class of riboregulatory elements, most of which act at the post-transcriptional level by base-pairing target mRNA genes. The RNA chaperone Hfq facilitates antisense interactions between target mRNAs and regulatory sRNAs, thus influencing mRNA stability and/or translation rate. In the α-proteobacterium Sinorhizobium meliloti strain 2011, the identification and detection of multiple sRNAs genes and the broadly pleitropic phenotype associated to the absence of a functional Hfq protein both support the existence of riboregulatory circuits controlling gene expression to ensure the fitness of this bacterium in both free living and symbiotic conditions. In order to identify target mRNAs subject to Hfq-dependent riboregulation, we have compared the proteome of an hfq mutant and the wild type S. meliloti by quantitative proteomics following protein labelling with 15N. Among 2139 univocally identified proteins, a total of 195 proteins showed a differential abundance between the Hfq mutant and the wild type strain; 65 proteins accumulated ≥2-fold whereas 130 were downregulated (≤0.5-fold) in the absence of Hfq. This profound proteomic impact implies a major role for Hfq on regulation of diverse physiological processes in S. meliloti, from transport of small molecules to homeostasis of iron and nitrogen. Changes in the cellular levels of proteins involved in transport of nucleotides, peptides and amino acids, and in iron homeostasis, were confirmed with phenotypic assays. These results represent the first quantitative proteomic analysis in S. meliloti. The comparative analysis of the hfq mutant proteome allowed identification of novel strongly Hfq-regulated genes in S. meliloti. © 2012 Sobrero et al. Source

Nystrom A.,Albert Ludwigs University of Freiburg | Thriene K.,Albert Ludwigs University of Freiburg | Thriene K.,Center for Biological Systems Analysis | Thriene K.,FRIAS Freiburg Institute for Advanced Studies | And 8 more authors.
EMBO Molecular Medicine | Year: 2015

Genetic loss of collagen VII causes recessive dystrophic epidermolysis bullosa (RDEB)-a severe skin fragility disorder associated with lifelong blistering and disabling progressive soft tissue fibrosis. Causative therapies for this complex disorder face major hurdles, and clinical implementation remains elusive. Here, we report an alternative evidence-based approach to ameliorate fibrosis and relieve symptoms in RDEB. Based on the findings that TGF-β activity is elevated in injured RDEB skin, we targeted TGF-β activity with losartan in a preclinical setting. Long-term treatment of RDEB mice efficiently reduced TGF-β signaling in chronically injured forepaws and halted fibrosis and subsequent fusion of the digits. In addition, proteomics analysis of losartan- vs. vehicle-treated RDEB skin uncovered changes in multiple proteins related to tissue inflammation. In line with this, losartan reduced inflammation and diminished TNF-α and IL-6 expression in injured forepaws. Collectively, the data argue that RDEB fibrosis is a consequence of a cascade encompassing tissue damage, TGF-β-mediated inflammation, and matrix remodeling. Inhibition of TGF-β activity limits these unwanted outcomes and thereby substantially ameliorates long-term symptoms. © 2015 EMBO. Source

Haaf E.,Center for Biological Systems Analysis | Schlosser A.,Center for Biological Systems Analysis | Schlosser A.,University of Wurzburg
Analytical Chemistry | Year: 2012

We have developed a new method that applies acidic catalysis with hydrochloric acid for 18O-labeling of peptides at their carboxyl groups. With this method, peptides get labeled at their C-terminus, at Asp and Glu residues, and at carboxymethylated cysteine residues. Oxygen atoms at phosphate groups of phosphopeptide are not exchanged. Our elaborated labeling protocol is easy to perform, fast (5 h and 30 min), and results in 95-97 atom % incorporation of 18O at carboxyl groups. Undesired side reactions, such as deamidation or peptide hydrolysis, occur only at a very low level under the conditions applied. In addition, data analysis can be performed automatically using common software tools, such as Mascot Distiller. We have demonstrated the capability of this method for the quantitation of peptides as well as for phosphopeptides. © 2011 American Chemical Society. Source

Weinberg F.,Albert Ludwigs University of Freiburg | Weinberg F.,Center for Biological Systems Analysis | Schulze E.,Albert Ludwigs University of Freiburg | Fatouros C.,Albert Ludwigs University of Freiburg | And 8 more authors.
Gene Expression Patterns | Year: 2014

Rio kinases are atypical serine/threonine kinases that emerge as potential cooperation partners in Ras-driven tumors. In the current study, we performed an RNAi screen in Caenorhabditis elegans to identify suppressors of oncogenic Ras signaling. Aberrant Ras/Raf signaling in C. elegans leads to the formation of a multi-vulva (Muv) phenotype. We found that depletion of riok-1, the C. elegans orthologue of the mammalian RioK1, suppressed the Muv phenotype. By using a promoter GFP construct, we could show that riok-1 is expressed in neuronal cells, the somatic gonad, the vulva, the uterus and the spermatheca. Furthermore, we observed developmental defects in the gonad upon riok-1 knockdown in a wildtype background. Our data suggest that riok-1 is a modulator of the Ras signaling pathway, suggesting implications for novel interventions in the context of Ras-driven tumors. © 2014 Elsevier B.V. All rights reserved. Source

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