5 research outputs found
Selective dynamical imaging of interferometric data
Recent developments in very long baseline interferometry (VLBI) have made it possible for the Event Horizon
Telescope (EHT) to resolve the innermost accretion flows of the largest supermassive black holes on the sky. The
sparse nature of the EHT’s (u, v)-coverage presents a challenge when attempting to resolve highly time-variable
sources. We demonstrate that the changing (u, v)-coverage of the EHT can contain regions of time over the course
of a single observation that facilitate dynamical imaging. These optimal time regions typically have projected
baseline distributions that are approximately angularly isotropic and radially homogeneous. We derive a metric of
coverage quality based on baseline isotropy and density that is capable of ranking array configurations by their
ability to produce accurate dynamical reconstructions. We compare this metric to existing metrics in the literature
and investigate their utility by performing dynamical reconstructions on synthetic data from simulated EHT
observations of sources with simple orbital variability. We then use these results to make recommendations for
imaging the 2017 EHT Sgr A* data sethttp://iopscience.iop.org/2041-8205Physic
Prise en compte de l'ecologie dans l'amenagement du territoire - Le cas de la commune de Lasne
SIGLEBSE B223482E / UCL - Université Catholique de LouvainBEBelgiu
In Vitro Reconstitution of the Functional Interplay between MCAK and EB3 at Microtubule Plus Ends
Insights into EB1 structure and the role of its C-terminal domain for discriminating microtubule tips from the lattice
End-binding proteins (EBs) comprise a conserved family of microtubule plus end–tracking proteins. The concerted action of calponin homology (CH), linker, and C-terminal domains of EBs is important for their autonomous microtubule tip tracking, regulation of microtubule dynamics, and recruitment of numerous partners to microtubule ends. Here we report the detailed structural and biochemical analysis of mammalian EBs. Small-angle X-ray scattering, electron microscopy, and chemical cross-linking in combination with mass spectrometry indicate that EBs are elongated molecules with two interacting CH domains, an arrangement reminiscent of that seen in other microtubule- and actin-binding proteins. Removal of the negatively charged C-terminal tail did not affect the overall conformation of EBs; however, it increased the dwell times of EBs on the microtubule lattice in microtubule tip–tracking reconstitution experiments. An even more stable association with the microtubule lattice was observed when the entire negatively charged C-terminal domain of EBs was replaced by a neutral coiled-coil motif. In contrast, the interaction of EBs with growing microtubule tips was not significantly affected by these C-terminal domain mutations. Our data indicate that long-range electrostatic repulsive interactions between the C-terminus and the microtubule lattice drive the specificity of EBs for growing microtubule ends