Roux Lab, Geneva

Roffay, C., Molinard, G., ..., & Roux, A. (2021). Passive coupling of membrane tension and cell volume during active response of cells to osmosis. Proceedings of the National Academy of Sciences of the United States of America, 118(47), e2103228118. #EpithelialMechanics
buff.ly/r1Hj7F6

Guillaume Pernollet shows that epithelial cells adjust their shape to locally flatten, forming scutoids for any geometry, changing our view of cell packing. Thanks to all! @clairedessalles.bsky.social @juanmagararc.bsky.social @sciencesunige.bsky.social
www.biorxiv.org/content/10.6...

@marineluciano.bsky.social recreates intestinal Villi geometry by growing epithelial cells on wavy rolling substrates. Unexpected intrication of curvature effects is observed. Thanks to all! @caterinatomba.bsky.social @sgabriele.bsky.social @sciencesunige.bsky.social
www.biorxiv.org/content/10.6...

Long-range chemical signalling in vivo is regulated by mechanical signals - Nature Materials Tissue stiffness mediated by Piezo1 is shown to regulate the expression of diffusive guidance cues in the developing Xenopus laevis brain, revealing a crosstalk between mechanical signals and long-ran...

Paper alert: Our study led by @evapillai.bsky.social and @sudimukherjee.bsky.social showing that mechanical properties of the #brain actively shape the molecular landscape during development and #axonpathfinding is finally out! www.nature.com/articles/s41... @pdncambridge.bsky.social @fau.de @MPZPM

congrats Joshua!

A great start to 2026! It was a pleasure to present my work on membrane asymmetry in the @rouxlab.bsky.social at the Geneva Chemistry and Biochemistry Days. It was also an honor to receive the Best Oral Presentation in Life Science!

A fantastic opportunity to work in Geneva if you are in the field of origins of life!

Today, our animation synthesizing decades of research on actin-mediated endocytosis in budding yeast was published:
journals.biologists.com/jcs/article/...

The result of a fantastic Iwasa-Drubin lab collaboration.

@margotriggi.bsky.social @jiwasa.bsky.social
movie.biologists.com/video/10.124...

Photo de moi et Élisabeth

Un très grand plaisir d'avoir pu enfin (après 5 ans) voir @elisabethbik.bsky.social en face à face à l'UNIL.

Elle y donne en plus un séminaire aujourd'hui.

All credits to the dreamteam that made this possible! what a pleasure and honor working with these people! 🥰
@diorgeps.bsky.social @mhakala.bsky.social @juanmagararc.bsky.social @joshuatran.bsky.social @mudgal17.bsky.social @Carlos Marcuello @Andrea Merino

The crucial test: We fused Heimdall Hofund to a fission-defective yeast ESCRT-III protein (Did2). This chimera restored Mup1 trafficking to vacuoles back to wt! A short amphipathic helix, present in Asgard and retained as fragments in eukaryotes, acts as a minimal membrane fission trigger!

Eukaryotic ESCRT-IIIA paralogs, known to form heteropolymers, retain Hofund elements at their N-termini.
In yeast, mutating these elements blocks ESCRT-III-dependent Mup1 transport to vacuoles.
So these elements matter in eukaryotes too.

Is this Asgard-specific, or conserved with their eukaryotic paralogs?
Hard to tell, since the exact molecular mechanism of fission by eukaryotic ESCRT-III remains blurry, probably due to its complexity.
Let’s figure it out!

Meet Hofund, the N-terminal amphipathic helix of 15 aa in Heimdall ESCRT-IIIA (named after Heimdall’s sword).
How do we know Hofund is the molecular trigger for fission?
Remove Hofund → ESCRT-IIIA loses fission activity.
Add Hofund alone → uncontrolled fission.

Through membrane fission! We show in vitro that the Asgard Heimdallarchaeota (Heimdall) ESCRT-IIIA subunit is inherently capable of triggering fission upon subunit turnover driven by ATP hydrolysis by Vps4.
And the key question: what actually destabilizes the membrane when ESCRT-IIIA turns over?

An Asgard archaeon with internal membrane compartments The emergence of eukaryotes from a merger between an archaeon and a bacterial cell ∼two billion years ago involved a profound change in cellular organisation. While the order in which different featur...

In a recent work, @buzzbaum.bsky.social and colleagues showed an Asgard archaeon with internal vesicles.
www.biorxiv.org/content/10.1...
How might Asgard ESCRT-III have contributed to compartmentalization?

Fantastic work from Javier @javierespadas.bsky.social in collaboration with @buzzbaum.bsky.social and @kaksonen.bsky.social labs, thank you Chris Toret, thank you Diorge @diorgeps.bsky.social!

Thanks to all the team at @rouxlab.bsky.social and abroad: @pauguillamat.bsky.social @caterinatomba.bsky.social @giodang.bsky.social @colomlab.bsky.social @lizhinde.bsky.social @javierespadas.bsky.social and many more

Overall, the work shows that tension gradients arise from the combination of actin dynamics and strong cell–substrate adhesion, rather than from migration itself.
Link: rdcu.be/eRTQA

We accompanied this dynamic live Flipper-TR FLIM imaging with lipid diffusion analysis, spatial lipidomics (shown below), and cool in vitro reconstitutions of tension gradients using supported lipid bilayers that are expanding

A key result: adherent cells maintain long-range membrane tension gradients even when they are not migrating! (micropatterned cells below)
In contrast, non-adherent migrating cells *do not* show these gradients.

Congrats Juanma! Thanks to all for your contributions in the long journey!

Active nematic pumps | PNAS Microfluidics involves the manipulation of flows at the microscale, typically requiring external power sources to generate pressure gradients. Alte...

Microfluidic pumping with active nematics! Self-organized and self-sustained. No external pumps.

@pnas.org @ub.edu

www.pnas.org/doi/10.1073/...

#ActiveMatter #Microfluidics #SoftMatter

Maria Tettamanti shows that inhibition of TORC2 by the small amphipath PalmC induces the TORC2-dependent internalization of sterols. Congrats to Maria and all coworkers involved, and to EMBOj for the efficient review process: use review commons! @biology-unige.bsky.social @sciencesunige.bsky.social

Etienne @membramics-lab.bsky.social is very happy to visit @rouxlab.bsky.social in Geneva! great people, great projects, good memories...

‪
Congratulations @centriolelab.bsky.social @dudinlab.bsky.social and @gautamdey.bsky.social for your publication in @cp-cell.bsky.social: Charting the landscape of #cytoskeletal diversity in #microbial eukaryotes #Expansion #Microscopy @sciencesunige.bsky.social
www.unige.ch/medias/en/20...

*ALL*source data and Python notebooks are available (you can reproduce all figures!)
🔗 doi.org/10.6084/m9.f...
We hope this helps make lifetime analysis transparent and comparable across setups.
📄 www.biorxiv.org/content/10.1...

@rouxlab.bsky.social
#FLIM #FlipperTR #Microscopy #OpenScience

Fluorescence lifetime estimation: a practical approach using Flipper-TR FLIM Flipper-TR is a membrane dye sensitive to lipid packing widely used to probe membrane tension in live cells via fluorescence lifetime imaging microscopy (FLIM). However, no consensus currently exists ...

🚨 New preprint out!
“Fluorescence lifetime estimation: a practical approach using Flipper-TR FLIM” with Tithi Mandal and @rouxlab.bsky.social
We benchmark and describe step-by-step Flipper-TR FLIM measurements across different set-ups and and strategies.

www.biorxiv.org/content/10.1...

I am pleased to 📣 today’s superb thesis defense by Christian Schroer on “Chemical strategies for studying lipid signaling and transport”. Part of his work was recently published in the JLR; the other part will follow soon. A very proud and somewhat tipsy “Doktorvater” 🥂

Research Assistant or Master Thesis worker, group Hakala Research Assistant or Master Thesis worker, group Hakala

Undergraduate/internship/master's thesis position: jobs.helsinki.fi/job-invite/4...