Combining mechanical and superresolution measurements to reveal the plasticity of the Nuclear Pore Complexes


Nuclear pore complexes (NPCs) are the only gateways between the nucleus and cytoplasm in eukaryotic cells, facilitating the transport of selected cargoes of size from a few up to hundred nanometers. This versatility implies an important pore plasticity. Here, by combining atomic force microscopy (AFM) and single molecule localization microscopy (SMLM), a group led by Christine Doucet and Pierre Emmanuel Milhiet from the IBM team revealed that the NPC basket is very soft and explores a large conformational landscape: apart from its canonical basket shape, it dives into the central pore channel or opens, highlighting how this structure can adapt, and let morphologically diverse cargoes shuttle through NPCs.


Structure and mechanics of the human nuclear pore complex basket using correlative AFM-fluorescence superresolution microscopy
Vial et al., Nanoscale, 15, 5756-5770 (2023)


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Phosphorylation motif dictates GPCR C-terminal domain conformation and arrestin interaction


Link to publication:

The signaling pathways of arrestin-dependent G protein-coupled receptors (GPCRs) are regulated by the phosphorylation state of its C-terminal domain. The molecular basis of the arrestin-receptor interaction is not fully understood. In this study, we investigated the impact of phosphorylation on the conformation of the C-terminal region of three rhodopsin-like GPCR (V2R, GHSR, and β2AR). Using phosphomimetic models, the team of Nathalie Sibille, in collaboration with the team of Jean-Louis Banères (IBMM), has identified pre-formed secondary structure elements, or short linear motifs (SLiMs), that undergo specific conformational transitions upon phosphorylation. It's important to note that such conformational transitions occur in the region interacting with arrestin-2. Thus, our results suggest a model in which the phosphorylation-dependent conformation of the C-terminal regions of GPCRs would modulate arrestin binding and consequently the signaling of arrestin-dependent pathways. This illuminates how signaling through GPCRs in the arrestin-dependent pathway could proceed, further paving our understanding of this central process in cell-cell communication.

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The “Impulscience” prize awarded to Ashley Nord

The Impulscience® program aims to reward and support excellent researchers in France, and to strengthen the attractiveness of France as a place of research to retain its talents and attract others. It meets two imperatives: preserving the freedom of innovation for researchers and supporting them over time.
Ashley Nord, CNRS biophysics researcher in the “Physics and mechanics of biological systems” Team at the CBS is one of the 7 winners this year. By studying the formation of bacterial biofilms through the prism of physical, it aims to radically disrupt everything that what we knew about them until now.

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Multi-scale dynamic imaging reveals that cooperative motility behaviors promote efficient predation in bacteria

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Overlay of Myxococcus xanthus bacteria trajectories
during the invasion of an Escherichia coli colony.


Publication link:
Rombouts, S., Mas, A., Le Gall, A. Fiche, J.B., Mignot, T., Nollmann, M.. Multi-scale dynamic imaging reveals that cooperative motility behaviors promote efficient predation in bacteria. Nat Commun 14, 5588 (2023).


Video: “Synchronized synergy: collective movement in Myxococcus xanthus”


Many species, such as fish schools or bird flocks, rely on collective motion to forage, prey, or escape predators. Likewise, Myxococcus xanthus forages and moves collectively to prey and feed on other bacterial species. These activities require two distinct motility machines enabling adventurous (A) and social (S) gliding, however when and how these mechanisms are used has remained elusive. Here, we address this long-standing question by applying multiscale semantic cell tracking during predation. We show that: (1) foragers and swarms can comprise A- and S-motile cells, with single cells exchanging frequently between these groups; (2) A-motility is critical to ensure the directional movement of both foragers and swarms; (3) the combined action of A- and S-motile cells within swarms leads to increased predation efficiencies. These results challenge the notion that A- and S-motilities are exclusive to foragers and swarms, and show that these machines act synergistically to enhance predation efficiency.

Insights into the "cocktail effect" of endocrine disruptors

Chemicals which taken in isolation are safe for humans may become harmful when mixed . The team of William Bourguet in Structural Biochemistry Center (Inserm / CNRS / University of Montpellier), together with teams from the Cancer Research Institute (IRCM ) and the Functional Genomics Institute (IGF ) in Montpellier elucidated in vitro a molecular mechanism that may contribute to this phenomenon known as the "cocktail effect".

New publication: "Synergistic activation of human pregnane X receptor by binary cocktails of pharmaceutical and environmental compounds"
Authors: Delfosse V, Dendele B, Huet T, Grimaldi M, Boulahtouf A, Gerbal-Chaloin S, Beucher B, Roecklin D, Muller C, Rahmani R, Cavaillès V, Daujat-Chavanieu M, Vivat V, Pascussi JM, Balaguer P, Bourguet W.
Journal: Nat Communication 2015 Sep 3;6:8089.