La place du volcanisme dévono-dinantien dans l'évolution magmatique et structurale de l'Europe moyenne varisque au Paléozoïque

International audienc

Pétrogenèse et évolution d'un complexe filonien ophiolitique: exemple du Troodos (Chypre)

Les premiers résultats de l'étude détaillée du complexe de dikes du Troodos confirment son caractère exceptionnel et montrent que plusieurs phases d'intrusions ont eu lieu pendant le « spreading » dont nous soulignons l'importance géotectonique. Nous proposons l'interprétation suivante : les dolérites grenues représentent le stade initial de formation du magma ophiolitique et le toit de la chambre magmatique, la première génération de dikes représente la phase majeure d'accrétion responsable de la formation de la croûte océanique. Cela est suivi par une seconde génération de dikes dont l'intrusion dépend de la fracturation du toit de la chambre magmatique. Les derniers dikes correspondent au stade final de l'activité de la dorsale

Spatial dynamics of receptor-mediated endocytic trafficking in budding yeast revealed by using fluorescent α-factor derivatives

Much progress defining the order and timing of endocytic internalization events has come as a result of real-time, live-cell fluorescence microscopy. Although the availability of numerous endocytic mutants makes yeast an especially valuable organism for functional analysis of endocytic dynamics, a serious limitation has been the lack of a fluorescent cargo for receptor-mediated endocytosis. We have now synthesized biologically active fluorescent mating-pheromone derivatives and demonstrated that receptor-mediated endocytosis in budding yeast occurs via the clathrin- and actin-mediated endocytosis pathway. We found that endocytic proteins first assemble into patches on the plasma membrane, and then α-factor associates with the patches. Internalization occurs next, concomitant with actin assembly at patches. Additionally, endocytic vesicles move toward early endosomes on actin cables. Early endosomes also associate with actin cables, and they actively move toward endocytic sites to capture vesicles being released from the plasma membrane. Thus, endocytic vesicle formation and capture of the newly released vesicles by early endosomes occur in a highly concerted manner, mediated by the actin cytoskeleton

Approche probabiliste et geostatistique des champs de fractures. Applications a des sites geothermiques. Annexes

CNRS RP 440 (113) / INIST-CNRS - Institut de l'Information Scientifique et TechniqueSIGLEFRFranc

Selection and stabilization of endocytic sites by Ede1, a yeast functional homologue of human Eps15

During clathrin-mediated endocytosis (CME), endocytic-site maturation can be divided into two stages corresponding to the arrival of the early and late proteins at the plasma membrane. The early proteins are required to capture cargo and position the late machinery, which includes proteins involved in actin assembly and membrane scission. However, the mechanism by which early-arriving proteins select and stabilize endocytic sites is not known. Ede1, one of the earliest proteins recruited to endocytic sites, facilitates site initiation and stabilization. Deletion of EDE1 results in fewer CME initiations and defects in the timing of vesicle maturation. Here we made truncation mutants of Ede1 to better understand how different domains contribute to its recruitment to CME sites, site selection, and site maturation. We found that the minimal domains required for efficient Ede1 localization at CME sites are the third EH domain, the proline-rich region, and the coiled-coil region. We also found that many strains expressing ede1 truncations could support a normal rate of site initiation but still had defects in site-maturation timing, indicating separation of Ede1 functions. When expressed in yeast, human Eps15 localized to the plasma membrane, where it recruited late-phase CME proteins and supported productive endocytosis, identifying it as an Ede1 functional homologue