La dinámica de los estados de fosforilación de las vías HOG y de las feromonas en levaduras

Comunicaciones a congreso

Mapping the interaction of Snf1 with TORC1 in Saccharomyces cerevisiae

Nutrient sensing and coordination of metabolic pathways are crucial functions for living cells. A combined analysis of the yeast transcriptome, phosphoproteome and metabolome is used to investigate the interactions between the Snf1 and TORC1 pathways under nutrient-limited conditions

Id4 promotes the elimination of the pro-activation factor ascl1 to maintain quiescence of adult hippocampal stem cells

Quiescence is essential for the long-term maintenance of adult stem cells but how stem cells maintain quiescence is poorly understood. Here we show that neural stem cells in the adult mouse hippocampus actively transcribe the pro-activation factor Ascl1 regardless of their activated or quiescent states. We found that the inhibitor of DNA binding protein Id4 is enriched in quiescent neural stem cells and that elimination of Id4 results in abnormal accumulation of Ascl1 protein and premature stem cell activation. Accordingly, Id4 and other Id proteins promote elimination of Ascl1 protein in neural stem cell cultures. Id4 sequesters Ascl1 heterodimerisation partner E47, promoting Ascl1 protein degradation and stem cell quiescence. Our results highlight the importance of non-transcriptional mechanisms for the maintenance of neural stem cell quiescence and reveal a role for Id4 as a quiescence-inducing factor, in contrast with its role of promoting the proliferation of embryonic neural progenitors

System-Wide Quantitative Proteomics of the Metabolic Syndrome in Mice: Genotypic and Dietary Effects

Advances in mass spectrometry have made the quantitative measurement of proteins across multiple samples a reality, allowing for the study of complex biological systems such as the metabolic syndrome. Although the deregulation of lipid metabolism and increased hepatic storage of triacylglycerides are known to play a part in the onset of the metabolic syndrome, its molecular basis and dependency on dietary and genotypic factors are poorly characterized. Here, we used an experimental design with two different mouse strains and dietary and metabolic perturbations to generate a compendium of quantitative proteome data using three mass spectrometric techniques. The data reproduce known properties of the metabolic system and indicate differential molecular adaptation of the two mouse strains to perturbations, contributing to a better understanding of the metabolic syndrome. We show that high-quality, high-throughput proteomic data sets provide an unbiased broad overview of the behavior of complex systems after perturbation

Hydroid diversity of Eilat Bay with the description of a new <i>Zanclea</i> species

<p>Eilat Bay is located at the southernmost tip of Israel in the Gulf of Aqaba (Red Sea). The list of hydroids currently known from there includes 51 species, and when extending it to the entire Red Sea, it includes 157 species belonging to 41 families. Nevertheless, the information regarding hydroids in the Gulf of Aqaba, and in particular in Eilat Bay, is not exhaustive. The aim of this work is to improve knowledge of hydroid biodiversity in this area. The specimens collected during the HyDRa project (Hydroid Diversity of the Northern Red Sea) revealed the presence of 27 species, 13 Anthoathecata and 14 Leptothecata, belonging to 17 families and 20 genera. Two families, Cladonematidae and Corynidae, and five genera, <i>Cladonema</i>, <i>Slabberia</i>, <i>Campanularia</i>, <i>Nemalecium</i> and <i>Lafoeina</i>, are new findings for the Red Sea. Furthermore, <i>Nemalecium lighti</i>, <i>Zanclea gallii</i> and the new species <i>Zanclea eilatensis</i> sp. nov. have never before been recorded in the Red Sea. <i>Zanclea eilatensis</i> sp. nov. lives in association with a bryozoan, has a monomorphic colony lacking a perisarc and only has stenoteles in the polyps. The medusa stage has two prominent perradial exumbrellar nematocyst pouches and two tentacles with about 50 cnidophores having long flagella and containing macrobasic euryteles. In the present work, 54% of the species were associated with other organisms, such as hydroids, corals and bryozoans. New ecological data about the <i>Zanclea–</i>scleractinian coral association are documented. The present investigation provides new information about diversity in the Red Sea, and in particular in Eilat Bay. In addition, our data also have significance for Mediterranean and Red Sea biodiversity conservation due to the recent expansion of the Suez Canal and the consequent possible increase in the introduction of nonindigenous species in both directions.</p> <p><a href="http://zoobank.org/urn:lsid:zoobank.org:pub:C9EA7333-B9DF-4888-A643-4D45E6CD31CB" target="_blank">http://zoobank.org/urn:lsid:zoobank.org:pub:C9EA7333-B9DF-4888-A643-4D45E6CD31CB</a></p

Target of Rapamycin Complex 2 Regulates Actin Polarization and Endocytosis via Multiple Pathways

Target of rapamycin is a Ser/Thr kinase that operates in two conserved multiprotein complexes, TORC1 and TORC2. Unlike TORC1, TORC2 is insensitive to rapamycin, and its functional characterization is less advanced. Previous genetic studies demonstrated that TORC2 depletion leads to loss of actin polarization and loss of endocytosis. To determine how TORC2 regulates these readouts, we engineered a yeast strain in which TORC2 can be specifically and acutely inhibited by the imidazoquinoline NVP-BHS345. Kinetic analyses following inhibition of TORC2, supported with quantitative phosphoproteomics, revealed that TORC2 regulates these readouts via distinct pathways as follows: rapidly through direct protein phosphorylation cascades and slowly through indirect changes in the tensile properties of the plasma membrane. The rapid signaling events are mediated in large part through the phospholipid flippase kinases Fpk1 and Fpk2, whereas the slow signaling pathway involves increased plasma membrane tension resulting from a gradual depletion of sphingolipids. Additional hits in our phosphoproteomic screens highlight the intricate control TORC2 exerts over diverse aspects of eukaryote cell physiology

Parallel feedback loops control the basal activity of the HOG MAPK signaling cascade

Tight regulation of the MAP kinase Hog1 is crucial for survival under changing osmotic conditions. Interestingly, we found that Hog1 phosphorylates multiple upstream components, implying feedback regulation within the signaling cascade. Taking advantage of an unexpected link between glucose availability and Hog1 activity, we used quantitative single cell measurements and computational modeling to unravel feedback regulation operating in addition to the well-known adaptation feedback triggered by glycerol accumulation. Indeed, we found that Hog1 phosphorylates its activating kinase Ssk2 on several sites, and cells expressing a non-phosphorylatable Ssk2 mutant are partially defective for feedback regulation and proper control of basal Hog1 activity. Together, our data suggest that Hog1 activity is controlled by intertwined regulatory mechanisms operating with varying kinetics, which together tune the Hog1 response to balance basal Hog1 activity and its steady-state level after adaptation to high osmolarity.F.L. is supported by a HFSPO post-doctoral fellowship. The Pelet and Peter laboratories are supported by grants of the Swiss National Science Foundation (SNF), and work in the Peter laboratory is funded by the European Research Council (ERC), the Swiss Initiative in Systems Biology SystemsX (RTD project YeastX) and the ETH Zurich. In addition grants from the Spanish Ministry of Economy and Competitiveness (BFU2012-33503 and FEDER), 2014 SGR (Generalitat de Catalunya) and the Fundación Marcelino Botín (FB). F.P. is a recipient of an ICREA Acadèmia award (Generalitat de Catalunya)

Parallel feedback loops control the basal activity of the HOG MAPK signaling cascade

Tight regulation of the MAP kinase Hog1 is crucial for survival under changing osmotic conditions. Interestingly, we found that Hog1 phosphorylates multiple upstream components, implying feedback regulation within the signaling cascade. Taking advantage of an unexpected link between glucose availability and Hog1 activity, we used quantitative single cell measurements and computational modeling to unravel feedback regulation operating in addition to the well-known adaptation feedback triggered by glycerol accumulation. Indeed, we found that Hog1 phosphorylates its activating kinase Ssk2 on several sites, and cells expressing a non-phosphorylatable Ssk2 mutant are partially defective for feedback regulation and proper control of basal Hog1 activity. Together, our data suggest that Hog1 activity is controlled by intertwined regulatory mechanisms operating with varying kinetics, which together tune the Hog1 response to balance basal Hog1 activity and its steady-state level after adaptation to high osmolarity.F.L. is supported by a HFSPO post-doctoral fellowship. The Pelet and Peter laboratories are supported by grants of the Swiss National Science Foundation (SNF), and work in the Peter laboratory is funded by the European Research Council (ERC), the Swiss Initiative in Systems Biology SystemsX (RTD project YeastX) and the ETH Zurich. In addition grants from the Spanish Ministry of Economy and Competitiveness (BFU2012-33503 and FEDER), 2014 SGR (Generalitat de Catalunya) and the Fundación Marcelino Botín (FB). F.P. is a recipient of an ICREA Acadèmia award (Generalitat de Catalunya)

Molecular MR imaging for the evaluation of the effect of dynamic stabilization on lumbar intervertebral discs

Abstract The dynamic stabilization of lumbar spine is a non-fusion stabilization system that unloads the disc without the complete loss of motion at the treated motion segment. Clinical outcomes are promising but still not definitive, and the long-term effect on instrumented and adjacent levels is still a matter of discussion. Several experiments have been devised in order to gain a better understanding of the effect of the device on the intervertebral disc. One of the hypotheses was that while instrumented levels are partially relieved from loading, adjacent levels suffer from the increased stress. But this has not been proved yet. The aim of this study was to investigate the long-term effect of dynamic stabilization in vivo, through the quantification of glycosaminoglycans (GAG) concentration within instrumented and adjacent levels by means of the delayed Gadolinium-Enhanced Magnetic Resonance Imaging of Cartilage (dGEMRIC) protocol. Ten patients with low back pain, unresponsive to conservative treatment and scheduled for Dynesys implantation at one to three lumbar spine levels, underwent the dGEMRIC protocol to quantify GAG concentration before and 6 months after surgery. Each patient was also evaluated with visual analog scale (VAS), Oswestry, Prolo, Modic and Pfirrmann scales, both at pre-surgery and at follow-up. Six months after implantation, VAS, Prolo and Oswestry scales had improved in all patients. Pfirrmann scale could not detect any change, while dGEMRIC data already showed a general improvement in the instrumented levels: GAG was increased in 61% of the instrumented levels, while 68% of the non-instrumented levels showed a decrease in GAG, mainly in the posterior disc portion. In particular, seriously GAG-depleted discs seemed to have the greatest benefit from the Dynesys implantation, whereas less degenerated discs underwent a GAG depletion. dGEMRIC was able to visualize changes in both instrumented and non-instrumented levels. Our results suggest that the dynamic stabilization of lumbar spine is able to stop and partially reverse the disc degeneration, especially in seriously degenerated discs, while incrementing the stress on the adjacent levels, where it induces a matrix suffering and an early degeneration