Denis Chrétien

Denis Chrétien

@dchretien.bsky.social

Microtubule and cryo-ET addict!

513 followers1.1K following96 posts

Denis Chrétien reposted

McGill University
@handle.invalid

Meet the Titan Krios 300 kV cryo-EM. 🔬 One of only 3 in Canada, this towering 4.5 m microscope reveals highly accurate structures of cells, proteins and more. A key tool for advancing medical research. 📷 Nature Index, Integrated Structural Biology Grenoble (ISBG)

Denis Chrétien reposted

Ben Engel
@cellarchlab.com

MemBrain v2 is on @natmethods.nature.com now? I never had a @biorxivpreprint.bsky.social with 164 citations before😅 ...Which is also to say: Thank you to the amazing #TeamTomo community, many of whom not only beta tested, but also contributed diverse training data. This one belongs to all of us! 🤗🔬🧪

Ricardo D. Righetto@lifeonthewedge.bsky.social

A wild publishing ride to get here... but finally! (first bioRxiv: January 5th, 2024 🙃) Amazing work from @lorenzlamm.bsky.social and colleagues 🤗 Special thanks to the community who jumped early on the boat, sharing feedback and training data to make MemBrain v2 a reality 🙏🏽

nature.comMemBrain v2: an end-to-end tool for the analysis of membranes in cryo-electron tomography - Nature MethodsMemBrain v2 enables streamlined analysis of membranes in cryo-electron tomography by providing user-friendly tools for membrane segmentation, membrane protein localization and spatial analysis, suppor...
Denis Chrétien
@dchretien.bsky.social

These microtubules exhibit remarkable structural heterogeneity with varying protofilament and helical-start numbers (as heterogeneous as in vitro-assembled microtubules). Even more intriguing: they contain an internal scaffold which may confer enhanced rigidity to support their functions.

Denis Chrétien
@dchretien.bsky.social

Dear #Cryo-EM and #Microtubule lovers. TubulePy is online at github.com/dchretien35/... TubulePy allows calculation of microtubule protofilament skew angles (θ) and helical parameters for different protofilament numbers (N) and helical-start numbers (S). (1/2).

github.comGitHub - dchretien35/TubulePy: TubulePy allows calculation of microtubule helical parameters to built models from PDB files.TubulePy allows calculation of microtubule helical parameters to built models from PDB files. - dchretien35/TubulePy
Denis Chrétien
@dchretien.bsky.social

It can be used for a 2D classification approach, and also to facilitate analysis of cryo-EM images of microtubules, with its companion TubuleJ. Any feedback will be welcomed. (2/2).

Denis Chrétien
@dchretien.bsky.social

Thanks for advancing the field! It's very nice to make these softs at the disposal of the cryo-EM/Microtubule community ;-)

Bui Lab @McGill@builab.bsky.social

Introducing CsMT: A new CryoSPARC workflow for high-resolution microtubule reconstruction based on novel PF-pair classification! You can reconstruct MTs entirely in CryoSPARC—zero custom scripts needed. Inspired & built through a fantastic collaboration with the Cianfrocco lab! tinyurl.com/kdpm86tw

Denis Chrétien reposted

EMBL Events
@events.embl.org

#EESMicrotubules brought together an amazing community of microtubule researchers last week 🥼 Thank you to our wonderful participants, speakers, and organisers for 4 days of outstanding science and thought-provoking discussions! We hope to see you again at the next edition.

Denis Chrétien reposted

Direct Electron
@directelectron.bsky.social

More throughput. More particles. More structures. On a JEOL CRYO ARM 300 II, Apollo sustained 1,820 movies/hour across a complete cryo-EM dataset—collecting over 500,000 particles and reconstructing apoferritin to 1.72 Å in a single afternoon. Read how: https://ow.ly/kEYn50ZjOFX

ow.lyHIGH-THROUGHPUT CRYO-EM WITH APOLLO - Direct ElectronUp to 2,904 movies per hour and sustained 1,820 movies per hour, reconstructing apoferritin at 1.72 Å in a single afternoon.
Denis Chrétien
@dchretien.bsky.social

Well done. But is GTP-tubulin in an expanded state at the tip of growing microtubules? Indeed, nobody knows 🤔

Wieczorek Lab@mike-wieczorek.bsky.social

New preprint! In collaboration with the Steinmetz Lab at PSI we report cryo-EM structures of microtubules at up to 1.9 Å (!) resolution & in different nucleotide state mimics, suggesting a mechanism for lattice-induced GTP hydrolysis and why it leads to catastrophe: tinyurl.com/7cjrf863

Denis Chrétien reposted

GIS IBiSA
@ibisa.net

La #plateforme TEM2C de l'UAR Biosit propose ses services en cryo-microscopie électronique, cryo-tomographie et cryo-CLEM pour la biologie structurale et cellulaire ➡️ www.ibisa.net/plateformes-... @cnrsbiologie.bsky.social @inserm.fr @rennesuniv.bsky.social

ibisa.netTransmission electron microscopy, cryo and CLEM (TEM2C)Approches intégrées de cryo-microscopie électronique, cryo-tomographie et cryo-CLEM pour la biologie structurale et cellulaire.
Denis Chrétien
@dchretien.bsky.social

Nice story 😎

Jo Judernatz@jojudernatz.bsky.social

Glad to see the work of my PhD on the manchette microtubule now out in @embojournal.org: doi.org/10.1038/s443...

doi.orgSPACA9 and MNMIP1 bridge the seam of spermatid manchette microtubules - The EMBO JournalThe manchette is a transient microtubule (MT)-based structure that is vital for the correct shaping of sperm during spermiogenesis. Throughout spermiogenesis, the manchette retains structural integrity for several days, raising the question of how its MTs are regulated. Here, using cryo-electron tomography of manchettes isolated from rat testes, we find that manchette MT ends are structurally diverse. We show that the MT-binding protein CLASP2 is present throughout the manchette and likely regulates both MT ends. Using cryo-electron microscopy single particle analysis and super-resolution microscopy, we reveal that SPACA9 and MNMIP1 (SH3D21) bind to the seam of manchette MTs from the luminal side. SPACA9 binds to both α- and β-tubulin of protofilament 1 but does not interact directly with protofilament 13, while MNMIP1 binds directly to protofilament 13. MNMIP1 further extends and threads through the MT lattice at the seam. Our study reveals a novel seam MT inner protein complex with a unique binding mode, providing a plausible explanation for MT regulation that maintains manchette integrity over an extended period.

Denis Chrétien reposted

Eugene Katrukha 🇺🇦
@ekatrukha.bsky.social

The new release of #BigVolumeBrowser (0.1.0) finally adds animation render functionality to it, plus some other navigation improvements and bug fixes. Here is a movie I've made for the microtubule network (via ExM) in different cell types. Contact me if you want it for educational/research purposes.

Denis Chrétien reposted

Leah
@hoxinsocks.bsky.social

I love us

Rebecca R Helm@rebeccarhelm.bsky.social

This deep sea creature is as sharp & clear as broken class, & can grow as long as your hand. This giant amphipod, (Cystisoma) only has two colored body parts: the dense orange stomach/egg pouch, & two MASSIVE eyes, which are a glittering holographic orange layer completely covering its head. 📽️ MBARI

Denis Chrétien
@dchretien.bsky.social

Looks cool, will try!

Allegretti Lab@matteoall.bsky.social

We're happy to announce our new preprint! 🐸 easymode: general pretrained networks for cellular cryo-ET. Segment ~20 cellular features – ribosomes, microtubules, mitochondria, nuclei & more – with zero model training. 🔗 doi.org/10.64898/202... 🧵👇

Denis Chrétien reposted

Christophe 🔬 Leterrier
@christlet.bsky.social

Check the little video they made from the interview (with the “Rolex” Rave skateboards tee-shirt 😆)

Christophe 🔬 Leterrier@christlet.bsky.social

I was interviewed by @snehakhedkar.bsky.social for The Scientist about our work using super-resolution microscopy to map the neuronal architecture, and make nice pictures along the way! Check the article here: www.the-scientist.com/super-resolu...

the-scientist.comSuper-Resolution Microscopy Helps Map Hidden Neuronal Architecture | The ScientistChristophe Leterrier uses advanced microscopy to uncover neurons’ intricate nanostructure and dynamics while creating striking images that bring brain science to life.
Denis Chrétien
@dchretien.bsky.social

Great discovery from Manuel Thery, even the Musée d'Orsay has a cytoskeleton 😍

Manuel Thery@manuelthery.bsky.social

#LivingArchitectures We put cells and cytoskeleton filaments on the architecture of the musée d'Orsay. www.musee-orsay.fr/fr/agenda/ev... Scientists of the #CytoMorphoLab adapted their protocols to illustrate the questions that keep them awake at night. -> Two shows on the 24th and 25th of January.

Denis Chrétien reposted

Aryan Taheri
@aryantaheri.bsky.social

How do #tubulin dimers assemble and disassemble to form the #microtubule #cytoskeleton? Our recent #cryo-EM structures, published in #ScienceAdvances, demonstrate the processes of tubulin biogenesis and degradation. Click on the video and link below to learn more! www.science.org/doi/10.1126/...

Denis Chrétien reposted

SBCF
@sbcf.bsky.social

Ready for #CellLaVie2026? Program & registration are live! Join us Oct 21–23, 2026 at Institut Pasteur, Paris, for multidisciplinary cell biology, imaging, talks, posters & outreach, w/ Manuel Théry's behind-the-scenes look at the Musée d’Orsay video-mapping project. www.atoutcom.com/cell-la-vie/

Denis Chrétien reposted

Quanta Magazine
@quantamagazine.org

A powerful electrical motor propels bacteria in virtually every gut and puddle on Earth. After 50 years, it has finally been understood. @nattyover.bsky.social reports: www.quantamagazine.org/what-physica...

quantamagazine.orgWhat Physical ‘Life Force’ Turns Biology’s Wheels? | Quanta MagazineThe bacterial flagellar motor is finally understood after 50 years. In its workings, columnist Natalie Wolchover finds the essence of life.
Denis Chrétien
@dchretien.bsky.social

Stunning 😍, congrats!!!

Ben Engel@cellarchlab.com

Across scales from cells🦠 to atoms⚛️ – We reveal how anaerobic #bacteria break down very stable aromatic compounds found e.g. in oil spills 🛢️ #Bioremediation #TeamTomo 🧪 🧶🧬 🔬 Awesome collab with Lena, Matthias, @schullerjm.bsky.social @rnfr2d2.bsky.social @tomaspascoa.bsky.social @tamb-o.bsky.social

Denis Chrétien reposted

Bui Lab @McGill
@builab.bsky.social

The cartwheel was first visualized ~70 years ago in the symbiont Trichonympha in the wood termite gut. We’ve discovered the cartwheel’s secret: a unique zigzag stacking of SAS-6 tetramers that facilitates the iconic 9-fold symmetry of cilia. #cellbiology #teamtomo #SAS6 #cartwheel

Denis Chrétien
@dchretien.bsky.social

Beautiful work 😍

Shweta Nandakumar@bucklingmt.bsky.social

Despite their high rigidity, microtubules (MTs) dynamically bend and buckle in cells. MT-self repair is inherent to their metastable nature, but it remains unclear whether just inherent repair mechanisms are sufficient to maintain MT integrity🧵 (1/9) www.biorxiv.org/content/10.1...

Denis Chrétien
@dchretien.bsky.social

A very nice study showing that there is no obvious relationship between tubulin compaction/expansion state and its nucleotide state. Indeed, there is no experimental data demonstrating that GTP-tubulin is expanded in the GTP-cap at microtubule growing ends.

cryoEM papers@cryoempapers.bsky.social

Microtubules in the axon are GDP bound but adopt a stable GTP-like expanded state pubmed.ncbi.nlm.nih.gov/41951886/ #cryoEM

Denis Chrétien
@dchretien.bsky.social

This concept is based on one GTP analogue (GMPCPP), and a GTP hydrolysis deficient recombinant version. But most other GTP/GDP-Pi analogues induce a compacted state of tubulin (GTPgS, BeF3-, AlF3-) similar to that of GDP-tubulin in microtubules. Let's humbly recognise that this issue remains 'open'.

Denis Chrétien reposted

Benoît Zuber
@benoitzuber.bsky.social

New paper in Nature Communications: we identified ANTXR2 (CMG2) as the cellular receptor for C. perfringens NetF toxin, causing hemorrhagic enteritis in dogs and foals. ANTXR2 was previously known as the receptor for anthrax toxin PA. doi.org/10.1038/s414...

doi.orgIdentification and structural characterization of anthrax toxin receptor 2 as the Clostridium perfringens NetF receptor - Nature CommunicationsThis study identifies ANTXR2 as the cellular receptor for Clostridium perfringens toxin NetF and determines its structure bound to the toxin using cryo-EM, revealing a distinct lateral binding mechani...

Denis Chrétien reposted

Vladimir Volkov 🇺🇦
@vladimirvolkov.bsky.social

Happy to see the first paper from the lab published in the EMBO J today: link.springer.com/article/10.1... In it, we reconstitute self-assembling cooperative oligomers of human Ndc80 and Ska kinetochore complexes that stabilise microtubule ends, and study these samples using cryoET and TIRF

link.springer.comMicrotubule end stabilisation by cooperative oligomers of Ska and Ndc80 complexes - The EMBO JournalDuring mitosis, properly aligned chromosomes stabilise microtubule ends with the help of kinetochores to ensure timely segregation of chromosomes. Microtubule-binding components of the human outer kin...

Denis Chrétien reposted

Atherton Lab KCL
@athertonlabkcl.bsky.social

Excited to see our @natcomms.nature.com paper out! #Cryo-EM reveals a #microtubule stimulated ADP-release transition state of #kinesin 1. The auto-inhibitory tail has no affect on motor domain conformations. Focussed subunit processing helps! #cryoEM #microtubules www.nature.com/articles/s41...

nature.comMicrotubule association induces a Mg-free apo-like ADP pre-release conformation in kinesin-1 that is unaffected by its autoinhibitory tail - Nature CommunicationsKinesin-1 utilizes ATP-driven conformational changes to transport vital intracellular cargoes along microtubules. The authors use cryo-EM to reveal a missing structural transition state of the kinesin...