Sam Lewis, Ph.D.

On my way to DC and looking forward to this exciting mini-symposium! #ASBMB26

Megan Doty et al discovered that myelin remains for weeks after cortical axons degenerate. We call the sheaths without an axon de-axoned myelin. During the slow, asynchronous, degeneration, microglia don't play a major role in clearing the axon or de-axoned myelin. www.science.org/doi/10.1126/...

Organelle-Targeted Laurdans Measure Heterogeneity in Subcellular Membranes and Their Responses to Saturated Lipid Stress - PubMed Organelles feature characteristic lipid compositions that lead to differences in membrane properties. In cells, membrane ordering and fluidity are commonly measured using the solvatochromic dye Laurdan, whose fluorescence is sensitive to lipid packing. As a general lipophilic dye, Laurdan stains all …

seen this? pubmed.ncbi.nlm.nih.gov/39069657/

Yes
bsky.app/profile/biot...

No Kings includes Draft Kings

We are organizing a mini-symposium on "Membrane and Organelle Dynamics" at ASBMB 2026! #ASBMB @asbmb.bsky.social
@aydinlab.bsky.social and I have put together a fantastic lineup of speakers for Day 1 morning. Come learn about some cutting-edge research in the field.

Thank you, Lorena! Happy to see this online 😁 🎉

Self-renewal of neuronal mitochondria through asymmetric division - preLights Neurons contain “hotspots” for mitochondrial biogenesis at distal branch points

Check out my first @prelights.bsky.social article, based on some great work done by Dr. Tejashree Waingankar & @samlewis.bsky.social at UC Berkeley 🔬🧬🧠

prelights.biologists.com/highlights/s...

How does molecular valency shape condensate assembly and function? We used the CO2-fixing organelle in algae—the pyrenoid—to find out… 🧵

Preprint here!:
www.biorxiv.org/content/10.6...

@cellarchlab.com @phaips.vd.st @biologyatyork.bsky.social
#Rubisco #PhaseSeparation #Condensates #Pyrenoid

Thank you!

@focalplane.bsky.social I recommend www.biorxiv.org/content/10.6...

I'm reading this now based on your recommendation, and it feels like listening to Bjork for the first time

I found me!

A lot of the time I would inject to guide them, as in "the authors chose to measure X to address their hypothesis; could they have measured something else instead? if they had measured Y, would that be a more direct test of their model or less direct, in your opinion?" etc, etc

I was pretty nervous at first. But luckily I didn't monologue much; someone asks a question, and my answer leads to another question, and then a student chimes in because we're verging on some topic relevant to their dissertation, and then they're in a discussion amongst themselves!

Teaching was easier and more fun for me as well. This worked without too much prep because the class was small, but now I'm thinking about how to adapt some features to a class of 30+

I will definitely do this again!

I taught my grad-level cell bio seminar using the Socratic method in the fall, and shockingly (to me), students loved it. No slides, just yapping. I assigned two research articles per week as the starting point, but we were mostly led by their questions

sorry to hear, Uri

I love this video of mitochondrial trafficking and POLG2-GFP in pLL neurons of live zebrafish larvae - from our awesome collaborator Katie Drerup @kdrerup.bsky.social at UW-Madison. She and her team are so talented!

I don't see any mtDNA...?

The cryo cyclical multiplexing expansion microscopy (Cy-ExM) preprint from
@seweryn-galecki.bsky.social , @kevin-dean.bsky.social et al is online.

20 targets across an entire cell. Mr. Snouty also joined the fun.

www.biorxiv.org/content/10.6...

The Raven Scholar, by Antonia Hodgson
The Devils, by Joe Abercrombie
The Angel of the Crows, by Katherine Addison

Self-renewal of neuronal mitochondria through asymmetric division Mitochondrial ATP production is essential for life. Mitochondrial function depends on the spatio-temporal coordination of nuclear and mitochondrial genome expression, yet how this coordination occurs ...

Congratulations to first-author Tejashree, and many thanks to our wonderful collaborators Diana Bautista and Katie Drerup! www.biorxiv.org/content/10.6...

Bottom line: peripheral sensory neurons pattern mitochondrial diversity using cell geometry!

By coupling mitochondrial self-renewal to axon branch points, neurons maintain energy and homeostasis from microns to meters! 10/10

We also show that axonal mitochondria almost never fuse with one another. That means once daughters differentiate, they keep their distinct identities instead of mixing back together 9/n

This asymmetric division actually *rejuvenates* the mother mitochondrion, boosting its membrane potential and keeping it dedicated to making new mitochondrial components 8/n

When these mitochondria divide, they do so asymmetrically. The “mother mitochondrion” keeps the mtDNA, while small, fast-moving daughters are shed with no mtDNA at all 7/n

🧬 At branch points, mitochondria actively copy and transcribe their mtDNA, stockpile mitochondrial mRNAs made in the nucleus, and sit next to sites where new proteins are being made 6/n

📍 These branch-point mitochondria are packed with mtDNA. In contrast, half of mitochondria along the axon have NO mtDNA at all! 5/n

🔬 Using high-resolution imaging in mouse DRG sensory neurons and zebrafish larvae, we discovered something unexpected: a special group of mitochondria parked right at axon branch points 4/n