Katrina Velle

I have been slacking on the #microscreepy season! Thanks for reposting!

Thanks for reposting!

They are both Naegleria gruberi— they are normally amoebae, but can transiently transform into a flagellate as a stress response

PhD or Master's position available for Fall 2026!

Interested in how actin drives cell crawling, eating, dividing, or osmoregulation? What about pathogenesis of a brain-eating amoeba? Or eukaryotic evolution? If so, apply through my website: katrinavelle.wixsite.com/science/cont...
Please share!

Poster with a picture of the speaker, Pablo Saez, advertising his talk: Decision Making during cell migrations. Abstract: Moving cells navigate inside living tissues often encountering obstacles and junctions, where their path branches into alternative directions of migration. This is the case of cells moving on top or within blood vessels, which often bifurcate into branches. Cells have diverse migratory strategies that differentially rely on the adhesion to the substrate. Cells that undergo mesenchymal migration are highly dependent on the adhesion to the substrate, and when facing bifurcations are forced to coordinate the adhesion and detachment of the competing branches. Recent studies showed how the decision is made -to keep or retract a branch and choose a new direction- when there is bias: open versus dead-end, differences in pressure, presence/absence of a chemoattractant. However, much less is know about how cells decide a new direction when the decision is unbiased. Similarly, it is poorly understood how migrating cells coordinate membrane dynamics during branching to maintain a good trade-off between microenvironmental exploration and migratory efficiency. Here, we use in vitro live-cell imaging using different levels of complexity, and advanced image analysis to analyze the response of migrating cells when facing symmetric junctions, and extreme branching when cells simultaneously face several bifurcations. We found that actin and membrane dynamics play a key role to choose a new direction path in both cases i) when cells face a single junction (Ron et al. 2024), and ii) when cells exhibit high levels of branching because they face several junctions at the same time (Liu et al.). In addition, we found that migrating immune cells have a fine tune regulation of branching in order to coordinate surveillance and migration. These results shed light on the mechanisms by which cells resolve unbiased junctions and branching during cell migration.

🚨 TLM Online Seminar Series - 08.10.25 | 16:00 UK
Pablo Sáez: "Decision-making during cell migration"

Please repost & to attend online please register to our 📧for the zoom link: lists.cam.ac.uk/sympa/subscr...

Cell Migration Seminars Cell Migration Seminars every Tuesday at 16:00 BST.

If anyone ever wants to brush up on a lot of cell migration concepts don't forget we have several wonderful scientists who have given talks previously in cell migration seminars. I find it so comforting to go look at old videos, maybe someone else who will do as well!!
youtube.com/@cellmigrati...

Arp2/3-mediated bidirectional actin assembly by SPIN90 dimers Nature Structural & Molecular Biology - Liu et al. show that SPIN90 dimerizes and binds two Arp2/3 complexes to nucleate two bidirectional actin filaments and the dimerization domain is...

And now for something completely different @tianyang22.bsky.social & #YanCao uncover of how SPIN90 dimers activate Arp2/3 to nucleate bidirectional linear actin filaments. Great collaboration with @romet-jegou-lab.bsky.social & @carolynmoores1.bsky.social #Cryo-EM #Arp2/3 rdcu.be/eGoH4

”Please inhibit responsibly: Natural and synthetic actin toxins as useful tools in cell biology”

I had a lot of fun going down different actin inhibitor rabbit holes with @onishilab.bsky.social on this perspective!

www.molbiolcell.org/doi/10.1091/...

www.molbiolcell.org/cms/10.1091/...

@fritzlaylin.bsky.social et al. propose a simple way to highlight both experimental #reproducibility & cell-to-cell variation, while avoiding pitfalls common in analysis of cell biology data rupress.org/jcb/article/...

📕 Reproducibility & Best Practices in Cell Biology: rupress.org/jcb/collecti...

📢📢Hiring 2 Research Assistants & 2 Postdocs at Emory University in Atlanta to study cytoskeletal biophysics/biochemistry. Please RT.

RAs: great for recent bachelor's/master's in Physics/Bio/Chem/Biochem. Email CV and interests to shekhar@emory.edu.

More info: www.shekharlab.org

Our latest preprint on the role of the Arp2/3 complex in mitotic entry is now available @biorxiv. This work was done by Dhanya Kalathil, a very talented postdoc in my lab. The story started in 2019 when we were investigating the role of branched actin in cytokinesis. 1/

The Origin and Diversification of Mitochondria Moving beyond the simplistic view of mitochondria as the power house of the cell, Roger et al. present the immense diversity of mitochondria and mitochondrial functions across eukaryotes, and bring th...

Feeling mitochondrially challenged lately?

Here are two classic reviews on #mitochondria that should help.

www.cell.com/current-biol...

www.cell.com/current-biol...

How did life get multicellular? Five simple organisms could have the answer Single-celled species that often stick together in colonies have researchers rethinking the origin of animals.

For some three billion years, unicellular organisms ruled Earth. Then, around one billion years ago, a new chapter of life began

go.nature.com/3JyRV4S

I'm growing (pun intended) pretty fond of the idea. Maybe at some point this semester!

Hey @arzaf.bsky.social how about a side project? 😄

New preprint online!

So much fun working on this project, thank you @centriolelab.bsky.social and @dudinlab.bsky.social for embarking me on this one!

Hopefully HAK-actin will become your best companion for actin staining U-ExM expanded samples.

#FluorescenceFriday

#Mitochondria, powerhouse of the #cell were labeled (cyan) and it's possible to visualize how they reach *every* corner to provide energy.

All recorded under the microscope @cellcommlab.bsky.social

#scicomm #sciencesky #microscopy #organelles @focalplane.bsky.social 🧪🔬

Who needs BioRender when you have #MSPaint?

www.cell.com/cell/abstrac...

Bethesda Declaration — STAND UP FOR SCIENCE Support NIH Staff Now!

Today, @nihfellowsunited.bsky.social staff sent a powerful letter to the NIH Director outlining serious concerns about the agency’s direction. Thousands have already signed in support—add your name. – Mary Munson, ASCB President www.standupforscience.net/bethesda-dec...

Glad to see some scientific society leadership stepping up to endorse the #BethesdaDeclaration

An amoeba movie I made: "hungry" #protistsonsky #amoeba

These courses are a remarkable opportunity for scientists to up their game. They'll learn tools and approaches that are transformative! Check it out! 🧪

I got hit by some rather sudden and extreme financial hardship so if anyone is in need of remote wetlab contract research, strictly BSL1, do let me know. Currently scrambling for gigs.

Plant, Bacterial, Archaeal Non-model Bioeng
Custom Lab Hardware
Turn Key Genetic Design

Please repost for reach 💚

This awesome @faseborg.bsky.social website offers detailed information about NIH and NSF funding to each and every state--use this a write!
www.faseb.org/science-poli...

Elon Musk and DOGE’s Savings May Be Erased by New Costs An expert on the federal work force estimates that the speed and chaos of Mr. Musk’s cuts to the bureaucracy will cost taxpayers $135 billion this fiscal year.

“Mr. Musk’s cuts to the bureaucracy will cost taxpayers $135 billion this fiscal year.”

That is 3 times the entire NIH budget

www.nytimes.com/2025/04/24/u...

Visas revoked from 13 UConn students, at least 40 others in CT The visas were revoked by the Trump administration and are part of an effort that has left hundreds of students nationwide at risk for deportation.

13 UConn (& 50+ CT) students have had their visas revoked.
"Rep. Greg Haddad, D-Mansfield, ... said...that there had been “no credible evidence” that any of the students who had their visas revoked had “violated the terms of their stay.”"

Students are freaking out, w/good reason. This is gross.

Excited to have @katrinavelle.bsky.social as our second keynote speaker. You all should check out the Velle Lab website for some beautiful sci-art posters! Also, join us at the virtual Spring Symposium - It's FREE and open to all! shorturl.at/zse9P

Two amoeba are floating against a black background. One has flagellates coming from its cell body in gold, and the other has a cyan dot in the center of the cell body. They are both purple and gold.

For #MicroscopyMonday, Naegleria cells from our Keynote Speaker for the Spring Symposium!🦠

🔬: Nikon Ti2, Plan Apo λ 100x oil obj, Crest spinning disk, Prime 95B CMOS, Spectra III/Celesta source
🥼: @katrinavelle.bsky.social
🏛️: www.umassd.edu
📩: info@nesmicroscopy.org

#NESM #SciComm #SciArt

Many others before me have optimized growing conditions, making my job significantly easier! Chan Fulton (Brandeis) has done a lot of work to identify optimal gruberi media, and Chris Rice (at Purdue, not on BlueSky?) was kind enough to share fowleri protocols!

We’re looking at the basic biology of these cells— how do they crawl, eat, divide etc. Knowing how all this works is a big 1st step towards designing new treatments. If this basic biology is conserved between the two species, we can go back to only using our benign system, and I will sleep better!