RNase E resolves toxic condensates by counteracting phase separation of Type II RhlB helicases

Article Article scientifique Article RNase E resolves toxic condensates by counteracting phase separation of Type II RhlB helicases eng 2026-08-12 2026-08-10 author Hausmann Stéphane Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, 1211 Geneva 4, Switzerland. 29303 Structure enseignement (ENSI) author Geiser Johan 0000-0003-0046-1723 Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, 1211 Geneva 4, Switzerland. 884774 Département de microbiologie et médecine moléculaire (MIMOL) author Vadas Oscar 0000-0003-3511-6479 Protein Biochemistry Platform, Faculty of Medicine, University of Geneva, 1211 Geneva 4, Switzerland. 508966 Département de microbiologie et médecine moléculaire (MIMOL) author Guex-Crosier Sylvain Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, 1211 Geneva 4, Switzerland. 923802 Département de microbiologie et médecine moléculaire (MIMOL) author Gonzalez Diego Laboratory of Microbiology, Institute of Biology, Faculty of Sciences, University of Neuchâtel, 2000 Neuchâtel, Switzerland. author Valentini Martina 0000-0002-1948-8339 Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, 1211 Geneva 4, Switzerland.,iGE3 Institute, University of Geneva, 1211 Geneva 4, Switzerland. 889251 Département de microbiologie et médecine moléculaire (MIMOL) gkag801 10.1093/nar/gkag801 42581758 0305-1048 PMC13462270 https://academic.oup.com/nar/article/doi/10.1093/nar/gkag801/8759378 In many Proteobacteria, the RNA helicase RhlB is a component of the RNA degradosome, a multi-protein complex involved in RNA processing and degradation. Within this complex, RhlB interacts with the scaffold endoribonuclease RNase E. In Escherichia coli, allosteric activation of RhlB by RNase E has defined the current paradigm for RhlB regulation. Here, we identify a distinct clade of RhlB helicases, exemplified by Pseudomonas aeruginosa RhlB, which we designate Type II. Unlike Type I RhlB, Type II RhlB helicases contain an N-terminal intrinsically disordered region that drives RNA-dependent liquid-liquid phase separation and enhances RhlB activity. Biochemical, structural, and functional analyses show that P. aeruginosa RNase E binds RhlB through an interface distinct from that described in the E. coli model and, rather than stimulating activity, antagonizes RhlB phase separation. Excessive RhlB condensation impairs bacterial growth at low temperature, and RNase E-mediated control of RhlB condensation maintains growth under these conditions. Together, these findings reveal that conserved RNA degradosome components can engage in distinct regulatory interactions across species and identify condensate dissolution as a novel mechanism regulating RNA helicase activity. Bacterial Proteins / chemistry Bacterial Proteins / genetics Bacterial Proteins / metabolism Endoribonucleases / chemistry Endoribonucleases / genetics Endoribonucleases / metabolism Escherichia coli / enzymology Escherichia coli / genetics Escherichia coli Proteins / chemistry Escherichia coli Proteins / genetics Escherichia coli Proteins / metabolism Models, Molecular Multienzyme Complexes Phase Separation Polyribonucleotide Nucleotidyltransferase Protein Binding Pseudomonas aeruginosa / enzymology Pseudomonas aeruginosa / genetics RNA Helicases / chemistry RNA Helicases / genetics RNA Helicases / metabolism Dewey 616 Dewey 590 Swiss National Science Foundation RNA degradosome reshuffling – an essential driver of bacterial adaptation 203343 CH 54 Département de microbiologie et médecine moléculaire 21B 23 Institut de génétique et de génomique 0DH false 443 Biologie d'un parasite intracellulaire obligatoire 773 1384 RNA Métabolisme et pathogenèse bactérienne 1036 Nucleic acids research 54 15 f9ffe57b-670b-46c2-82ca-1b3261e0bac9 Article (Published version) Public gkag801.pdf 3208873 application/pdf CC BY-NC-4.0 e525638d6c7dae4651ca34ec3698703bb5c44897691dd1ad7e4bcbda5454382b 2f571bde-ec1e-4c2a-bffb-99cccacb4012 Supplemental data Public Table_S3.xlsx 211146 application/vnd.openxmlformats-officedocument.spreadsheetml.sheet 3a8b7225a870f3fa9a25032aaf243454f6cc8efcc08d9619b8d5e1c94d2a2a69 b4b69225-c740-4f24-969d-2724753940b3 Supplemental data Public Hausmann_et_al_2026_Supplementary_i.pdf 2405729 application/pdf 0f6dfd8ef541a17382c81b8d9fb206cb18c4bf2a9d6973eee2e224854149765c 7e00c953-3dc0-4bb2-a985-940513b0bc5c Supplemental data Public Figure_S1.pdf 224381 application/pdf fe47387c383cbc0c64ac9c820c698baaea6d2e7bf701e328b02a89cbd4cd07fb Vignette Public Sans titre.jpg 128365 image/png openAccess Faculté de médecine / Section de médecine fondamentale / Département de microbiologie et médecine moléculaire Centres et instituts / Institut de génétique et de génomique

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RNase E resolves toxic condensates by counteracting phase separation of Type II RhlB helicases	Nucleic acids research	2026	1	0
Studying the contribution of the Pseudomonas aeruginosa RNA degradosome in bacterial adaptation to cystic fibrosis lungs		2024	152	4

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