Structural insights into the catalysis and regulation of E3 ubiquitin ligases

Covalent attachment (conjugation) of one or more ubiquitin molecules to protein substrates governs numerous eukaryotic cellular processes, including apoptosis, cell division and immune responses. Ubiquitylation was originally associated with protein degradation, but it is now clear that ubiquitylation also mediates processes such as protein–protein interactions and cell signalling depending on the type of ubiquitin conjugation. Ubiquitin ligases (E3s) catalyse the final step of ubiquitin conjugation by transferring ubiquitin from ubiquitin-conjugating enzymes (E2s) to substrates. In humans, more than 600 E3s contribute to determining the fates of thousands of substrates; hence, E3s need to be tightly regulated to ensure accurate substrate ubiquitylation. Recent findings illustrate how E3s function on a structural level and how they coordinate with E2s and substrates to meticulously conjugate ubiquitin. Insights regarding the mechanisms of E3 regulation, including structural aspects of their autoinhibition and activation are also emerging

QCD and strongly coupled gauge theories : challenges and perspectives

We highlight the progress, current status, and open challenges of QCD-driven physics, in theory and in experiment. We discuss how the strong interaction is intimately connected to a broad sweep of physical problems, in settings ranging from astrophysics and cosmology to strongly coupled, complex systems in particle and condensed-matter physics, as well as to searches for physics beyond the Standard Model. We also discuss how success in describing the strong interaction impacts other fields, and, in turn, how such subjects can impact studies of the strong interaction. In the course of the work we offer a perspective on the many research streams which flow into and out of QCD, as well as a vision for future developments.Peer reviewe

Intertidal mussel beds from the South-western Atlantic show simple structure and uniform appearance: does environmental harshness explain the community?

Communities of the rocky mid-intertidal zone of the South-western Atlantic are uniform in appearance, dominated by dense monocultures of small-size mussels (Brachidontes rodriguezii and Perumytilus purpuratus). To explain this, two hypotheses have been advanced in the literature: environmental harshness due to high potential evaporation and historical contingency after the Last Glacial Maximum. In this study of Uruguayan and Argentine shores, we address the implications and predictions of these two hypotheses from a biogeographic perspective by studying the regional distribution and composition of mid-intertidal mussels. We conducted an extensive latitudinal sampling survey (21 locations, 34–54°S), along with a compilation of available information on mussel bed composition and mussel predators present along the coastline. Then we constructed latitudinal profiles of ecologically significant environmental variables with specific emphasis on potential evaporation, a proxy for desiccation stress. The results show that mussel beds are composed of two species of small mussels, which coexist over a biogeographic transition zone (40–42°S) related to sea surface water temperature. The distribution of mussels along the coastline studied is not consistent with the environmental harshness hypothesis. In addition, in the Central Patagonian zone (44–50°S), two invertebrate predators also inhabit the intertidal rocky shores. However, these localities showed higher environmental harshness (potential evaporation rate) than non-Patagonian localities. We suggest that further attention should be given to historical contingency in order to advance towards a hypothesis consistent with current knowledge on the post-glacial biogeographic history of the South-western Atlantic.Fil: Adami, Mariana Laura. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de la Plata. Facultad de Ciencias Naturales y Museo. División Zoología Invertebrados; ArgentinaFil: Schwindt, Evangelina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; ArgentinaFil: Tablado, Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; ArgentinaFil: Calcagno, Javier Ángel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Maimónides. Área de Investigaciones Biomédicas y Biotecnológicas. Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y de Diagnóstico; ArgentinaFil: Labraga, Juan Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Orensanz, Jose Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentin