Andrea Vettiger

I am delighted to share our latest paper on mycomembrane protein assembly which came out last week in @pnas.org This was a fantastic collaboration between my former colleague, Elizabeth (#Betsy) Hart, and my first PhD student, Dieuwertje (#Didi) de Bruin. www.pnas.org/doi/10.1073/... (1/n)

Andrea Vettiger reposted

Will Ratcliff

@wcratcliff.bsky.social

Out today in @nature.com: our review on how single cells evolve into multicellular organisms. With Ozan Bozdag, @kaitong25.bsky.social, Peter Yunker, and @matthewherron.bsky.social. rdcu.be/9ZuiKow9twKa For an overview, check out the video below.

Andrea Vettiger reposted

Alexander Harms

@aharms485.bsky.social

The final version of our manuscript on TnSeq in bacteriophages (“HIDEN-SEQ”) is out today – if you have an interesting phage phenotype and want to know the underlying genetic basis, this one is for you! 1/4

So, like Gram-negative bacteria, Cglu inserts its outer membrane proteins at zones of new cell wall insertion, even though it has no BAM complex 🧐 Many, many more open questions remain to be discovered in this exciting pathway and we hope to play a part in this! (10/n)

Last, shout out to Betsy who is opening her independent lab @universityofga.bsky.social in 2027 and will be recruiting soon 👀

Didi also supervised Marina, a talented Master's student, who showed that ProtX, another mycomembrane protein, is also inserted at the poles. Strikingly, once inserted, PorH & ProtX stay put, even though the mycomembrane lipids around them diffuse freely. (8/n)

Betsy then showed, that PorH and ProtX co-purify with the mAGP sacculus and interfering with AG biosynthesis weakens this interaction. Therefore, we conclude that these proteins are tightly linked to the underlying cell wall. (9/n)

I told Betsy whether she ever thought of imaging the spatiotemporal insertion dynamics using live-cell fluorescence microscopy 🔬 This was just prior to my departure in Boston, and thus we agreed that we would continue to collaborate on this once my lab was up and running @dmf-unil.bsky.social (6/n)

In comes Didi, my first PhD student. Didi mastered the whole cell biology side of the project and did an amazing job at showing where and when PorH gets incorporated: The sites of active cell wall remodeling a.k.a the old and new poles! (7/n)

PorH needs its partner PorA to reach the surface, and at least one of the pair must be O-mycoloylated by Cmt1 at Ser residues. Block mycoloylation on both and PorH piles up in off-pathway forms, reminiscent of assembly-defective OMPs in E. coli. Moreover, the T7SS secretion isn't required. (4/n)

According to AlphaFold2 PorAH likely forms hetero-pentameric channel with a hydrophilic lumen and a hydrophobic outer surface. Deletion of either gene results in increased Kanamycin resistance further supporting its role as an integral channel in the mycomembrane (5/n).

This story was spearheaded by Betsy, a former postdoctoral colleague of mine in Tom Bernhardt's lab at HMS. Betsy used a clever Tn-Seq screen to uncover the σ-D envelope stress response in Cglu using Tn-Seq in combination with a PorH surface display assay doi.org/10.1371/journal.pgen.1011127 (2/n)

doi.orgdoi.org

This screen also revealed, that PorH surface localization also depends to its operon partner, PorA. Based on that, Betsy started to investigate how these two proteins oligomerize into a mature surface exposed porins. Here is what we found: (3/n)

Andrea Vettiger reposted

Georgia Isom

@georgiaisom.bsky.social

23 July

One week left to apply!

Georgia Isom@georgiaisom.bsky.social

Interested in joining our group in Oxford? We are looking for a PDRA with single particle Cryo-EM experience to help us figure out how sphingolipids are transported to the cell surface of Gram-negative bacteria. The deadline is 31st July. Informal enquires are welcome. Please share!

my.corehr.comJob Details

doi.orgThe penicillin-binding protein PBP1b fortifies the Escherichia coli division site against osmotic rupture - Nature MicrobiologyA specific isoform of PBP1b functions independently of the activator protein, LpoB, to drive generation of a wedge-like peptidoglycan structure that strengthens the division site in Escherichia coli.

3 July

Excited to see our story published in @natmicrobiol.nature.com today! It’s been a long journey. We answered a major outstanding question: why does E. coli encode two aPBPs, yet only one plays a critical role in ensuring reliable PG fortification during cell division?

Paula Navarro@navarropaula.bsky.social

🚨 New in @natmicrobiol.nature.com! We reveal how the antibiotic target PBP1b fortifies the E.coli division site against osmotic rupture. Proud this was completed in our independent labs @dmf-unil.bsky.social, with @avettiger.bsky.social. Congratulations to all authors! 🦠❄️🔬 #teamtomo bit.ly/3SCbOg1 👇

jic.ac.ukIndependent Research Fellowships Leading to Tenured Faculty Positions | John Innes CentreThe John Innes Centre (JIC), is a world leading centre of excellence in plant and microbial sciences based on the Norwich Research Park, UK. We are inviting applications from outstanding researchers…

3 July

As always great collaboration with @navarropaula.bsky.social lab at @dmf-unil.bsky.social and the Bernhardt lab at @harvamed.bsky.social

Andrea Vettiger reposted

Géraldine Laloux

@lalouxlab.bsky.social

20 Nov 2025

Apply now to attend the next EMBO Bacterial Networks meeting #EMBOBacNet 🗓️13-18 September 2026 📍Sant Feliu de Guixols, Spain 📝Program and registration info: meetings.embo.org/event/26-bac... 👩‍🔬Organised with co-chair @s-lab.bsky.social and ECR @coralietesseur.bsky.social #MicroSky

Andrea Vettiger reposted

Tung Le

@tunglejic.bsky.social

3 Oct 2025

Independent research fellowships leading to tenured positions at the John Innes Centre. Repost = nice. Thank you very much!!!

John Innes Centre@johninnescentre.bsky.social

Shortlisted candidates will be invited to give a seminar at the Fellows Conference, which will be held on 10 March 2026. Candidates who win Fellowships will be offered a Tenure Track Group Leader position from the outset, initially for 5 years. Find out more: www.jic.ac.uk/training-car...

Andrea Vettiger reposted

Kevin Whitley

@kevindwhitley.bsky.social

6 May 2025

Postdoc position available! This is a 2-year post funded by the Academy of Medical Sciences. You'll be based in the Centre for Bacterial Cell Biology here in Newcastle, using super-resolution microscopy to look at the bacterial cell wall. 🔬🦠 Please re-post 🙏 www.jobs.ac.uk/job/DMY885/r...

jobs.ac.ukResearch Assistant/Associate - Mapping the Bacterial Cell Wall with Super-resolution Microscopy at Newcastle UniversityApply for the Research Assistant/Associate - Mapping the Bacterial Cell Wall with Super-resolution Microscopy role on jobs.ac.uk, the top job board for academic positions in higher education. View det...

30 Aug 2025

The Vettiger Lab at #SSM2025 last week. Was good fun! Looking already forward to 2026 in Montreux 😃

nature.comStreptomyces uses both polar and dispersed cell wall synthesis during exploratory growth - Nature MicrobiologyStreptomyces venezuelae requires MreB1-dependent dispersed peptidoglycan cell wall synthesis and DivIVA-mediated polar cell wall synthesis during its rapid exploratory growth phase.

11 Aug 2025

Super interesting finding: polar growth and dispersed growth are not mutually exclusive! Congrats to the authors 👌

Nature Microbiology@natmicrobiol.nature.com

#NewResearch Streptomyces use both polar and dispersed cell wall synthesis during rapid, exploratory growth @mcmasteriidr.bsky.social #BacteriaCellWall #MicroSky 🦠 www.nature.com/articles/s41...

wwwfbm.unil.chDMF: Tenure Track Assistant Professor towards Associate Professor in Molecular Microbiology - Site des postulations FBM

22 July 2025

Research is under pressure worldwide. But science still thrives ✊ Join us @dmf-unil.bsky.social – great colleagues, great science, and thus far reasonable government and funding agencies. Still time to apply! 🤞

Jan-Willem Veening@veeninglab.com

New tenure track assistant professor position in molecular microbiology in our department @dmf-unil.bsky.social @unil.bsky.social! We are casting a wide net for an experimental molecular microbiologist. Apply here: wwwfbm.unil.ch/releve/appli...

Andrea Vettiger reposted

Paul Hoskisson 🧫 🦠🐸

@paulhoskisson.bsky.social

20 July 2025

Superbugs could kill millions more and cost $2tn a year by 2050, models show www.theguardian.com/society/2025...

theguardian.comSuperbugs could kill millions more and cost $2tn a year by 2050, models showExclusive: Research on burden of antibiotic resistance for 122 countries predicts dire economic and health outcomes

doi.orgStress-mediated growth determines Escherichia coli division site morphogenesis | PNASIn order to proliferate, bacteria must remodel their cell wall at the division site. The division process is driven by the enzymatic activity of pe...

20 July 2025

Great to see this out in @pnas.org. A great effort led by Petr Pelch and Christoph Allolio at @charlesuni.cuni.cz who developed a new morphoelastic model for PG biogenesis and cell division.

Paula Navarro@navarropaula.bsky.social

So happy to have contributed to this beautiful study led by PetrPelech! A combined theory–experiment effort based on our in situ cryo-ET data, revealing how stress-mediated growth shapes E. coli division site morphogenesis. #teamtomo 🌐 🦠🔬❄️🐎 👉📄 doi.org/10.1073/pnas...

biorxiv.orgThe aPBP-type cell wall synthase PBP1b plays a specialized role in fortifying the Escherichia coli division site against osmotic ruptureA multi-protein system called the divisome promotes bacterial division. This apparatus synthesizes the peptidoglycan (PG) cell wall layer that forms the daughter cell poles and protects them from osmo...

It has been coming a long way... happy to share our latest work with you: www.biorxiv.org/content/10.1... Here, we show the importance of septal fortification by the Class A Penicillin Binding Protein, PBP1b, in E. coli and provide a molecular mechanism for this function. (1/12).

Based on AlphaFold prediction, this PBP1b-FtsA interaction is conserved among many Enterobactericae (in red) but not beyond. However, similar intrinsically disordered domains are found on most PBP1b and may offer a way to regulate aPBP activity independent of Lpo's. (11/12)

This work was carried out largely as part of a fantastic postdoc in Tom Bernhardt's lab at @harvardmed.bsky.social. @navarropaula.bsky.social and myself both started our own labs at @dmf-unil.bsky.social last year and just received some funding. Job post on related topics will follow soon 😃 (12/12)

To our surprise the peptide of PBP1b was predicted to interact with the same residue on FtsA than FtsZ. This may suggest a competitive binding for FtsZ and PBP1b to FtsA. Thanks to Roman Hajdu in @nartimsoole.bsky.social lab, we find evidence for this in supported lipid bilayer assays 🧪🔬 (9/12)

In the previous movie FtsZ (yellow) gets displaced from FtsA (unlabeled) upon addition of the wt N-terminal peptide of PBP1b (magenta), but not the R6E point mutant 👇 (10/12)

onlinelibrary.wiley.comonlinelibrary.wiley.com

The GFP fusion to the PBP1b-alpha isoform indeed does display a biased septal localization pattern unlike the shorter gamma isoform. This is supported by previous findings using immunofluorescence by Tanneke den Blaauwen and Waldemar Vollmer's group (onlinelibrary.wiley.com/doi/10.1111/...) ✅ (7/12)

But how does the N-terminal peptide of PBP1b mediate septal recruitment? AlphaFold screen performed by @ernstschmid.bsky.social in Johannes Walker's lab predicted an interaction with FtsA via a salt bridge between FtsA(E303) and PBP1b(R6) 🖥️ (8/12)

This lysis phenotype is specific for cells undergoing division. When inhibiting divisome formation with SulA expression, cells lacking PBP1b lyse significantly less, and when they do, they display smaller lesions which are likely attributed to the impaired side wall repair 🛠️ (6/12)

Interestingly, septal fortification of PBP1b doesn't seem to depend on its canonical Lpo activator, LpoB. However, it is dependent on the N-terminal cytosolic peptide of PBP1b, which was omitted in previous GFP fusions resulting in uniform IM labeling pattern 🤔 (6/12)

And their septal cell walls show compromised integrity (more pores and less stiff) when measured by AFM ⚛️🔬 (4/12).

Having such compromised septa leads to catastrophic lysis events under osmotically stressed conditions originating from the division site (green = released DNA) 🌊🔬(5/12)

aPBPs are a major cell wall synthase family and have been implemented in PG repair and fortification. Additionally, PBP1b has been proposed to play a crucial role in cell division however its precise role has remained obscure. (2/12)

Using in situ cryo-ET (as always performed by @navarropaula.bsky.social) we show that cells lacking PBP1b fail to produce a so-called septal PG wedge (highlighted by the red arrow) ❄️🔬 (3/12)

2 Apr 2025

Good news from the @snsf-ch.bsky.social was in the mail last week 😃 We will be recruiting soon...! More good news to be released in the coming days❗ Follow @navarropaula.bsky.social and myself for more bacterial cell envelope biology🔬🧬🦠🧫

Paula Navarro@navarropaula.bsky.social

Double the grants, double the money, double the impact! Huge thanks to our amazing teams -proof that scientific power couples thrive in inclusive, diverse and open-minded institutions. And the real winner? Science, of course!🏆🔬Grateful beyond words! ❄️🐎 @dmf-unil.bsky.social @snsf-ch.bsky.social