Membrane association of the bacterial riboregulator Hfq and functional perspectives.

Association membranaire du riborégulateur Hfq et perspectives fonctionnelles.

Antoine Malabirade (1, 2) , Javier Morgado-Brajones (3, 1) , Sylvain Trépout (4) , Frank Wien (5) , Ileana Marquez (3) , Jérôme Seguin (6) , Sergio Marco (4) , Marisela Velez (3) , Véronique Arluison (7, 1)

1 LLB - UMR 12 - Laboratoire Léon Brillouin
2 UP11 - Université Paris-Sud - Paris 11
3 Instituto de Catálisis y Petroleoquímica
4 Chimie, Modélisation et Imagerie pour la Biologie [Orsay]
5 SSOLEIL - Synchrotron SOLEIL
6 I2BC - Institut de Biologie Intégrative de la Cellule
7 UPD7 - Université Paris Diderot - Paris 7

Hfq is a bacterial RNA binding protein that carries out several roles in genetic expression regulation, mainly at the post-transcriptional level. Previous studies have shown its importance in growth and virulence of bacteria. Here, we provide the direct observation of its ability to interact with membranes. This was established by co-sedimentation assay, cryo-transmission electron (cryo-TEM) and atomic force (AFM) microscopies. Furthermore, our results suggest a role for its C-terminus amyloidogenic domain in membrane disruption. Precisely, AFM images of lipid bilayers in contact with Hfq C-terminus fibrils show the emergence of holes with a size dependent on the time of interaction. Cryo-TEM observations also show that liposomes are in contact with clusters of fibrils, with occasional deformation of the vesicles and afterward the apparition of a multitude of tiny vesicles in the proximity of the fibrils, suggesting peptide-induced breakage of the liposomes. Finally, circular dichroism spectroscopy demonstrated a change in the secondary structure of Hfq C-terminus upon interaction with liposomes. Altogether, these results show an unexpected property of Hfq and suggest a possible new role for the protein, exporting sRNA outside of the bacterial cell.

Domaines: Biochimie, Biologie Moléculaire; Biophysique; Biologie structurale [q-bio.BM]; Réseaux moléculaires [q-bio.MN]; Organisation et fonctions cellulaires [q-bio.SC]

Antoine Malabirade, Javier Morgado-Brajones, Sylvain Trépout, Frank Wien, Ileana Marquez, et al.. Membrane association of the bacterial riboregulator Hfq and functional perspectives.. Scientific Reports, 2017, 7, pp.10724. ⟨10.1038/s41598-017-11157-5⟩. ⟨cea-01591449⟩