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

Link to publication: 
https://www.sciencedirect.com/science/article/abs/pii/S0969212623002897?dgcid=author

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.

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.

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

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). https://doi.org/10.1038/s41467-023-41193-x

Video: “Synchronized synergy: collective movement in Myxococcus xanthus”
https://www.wibbitz.com/watch/b603898e8c7d54592955b58828cb8d349/?cl=#5c6168&cl4=%2315324e&lg=8132e369779d4f878702ab25f531c8cf&type=produced

Abstract
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.

2D DNA-origami assembly for Cryo-EM Applications

We propose a self-assembled DNA origami honeycomb 2D-lattice as a molecular imaging scaffold for Cryo-Electron Microscopy (Cryo-EM). The thin, micrometer-scale supporting scaffold is able to cover extended areas of the holey carbon film and sufficiently resilient to withstand blotting and plunge-freezing forces. Furthermore, the DNA binding sites can be chemically engineered for selective surface-affinity trapping. We demonstrate the advantages of the method to facilitate membrane vesicles sample preparation. This includes increasing the local density of the vesicles, enabling the study of low-abundance membrane complexes, and purifying heterogenous samples by isolating vesicles from cell conditioned medium.