Great first post!

We have a pink frog in our lab today… already knocked over an Erlenmeyer 😆

Don’t forget rejecting submissions because it’s over the word count… before it even gets seen by a scientist! Dealing with that now 😞

Thanks Kathrin! Meghan (first co-author) did the actin imaging that you saw and of course you know Lana 🤓

Thanks! Reposted link.

So this preprint opens up many new questions in astrocyte cell biology!

This was a real team effort:
- Postdoc Will Barclay started the project at the NIH
- Postbac Johanna Bergstrom and undergrad Eva Lopez analyzed data
- PhD student Lana Ho contributed imaging data

Many distal ends are enriched in GFAP.

We don't know what this means yet - maybe these can become endfeet that contact blood vessels. Astrocyte processes are heterogeneous in vivo (some contact blood vessels, others contact synapses) - like axons vs. dendrites in neurons.

7/x

By cryo-ET, we could see a lot of intermediate filaments (IFs). The ratio of IFs:microtubules was very high ~7:1.

Image below shows: IFs (blue), microtubules (green), actin (yellow).

6/x

Microtubules in primary processes are highly stable as indicated by:
- Acetylation
- Detyrosination
- MIPs (microtubule inner proteins)
- IF content

5/x

And we confirmed this with cryo-ET.

4/x

We used live-cell imaging with plus-end binding protein EB3 to determine microtubule polarity in astrocytes for the first time. They are ~88% plus-ends out.

3/x

We isolated astrocytes using the immunopanning method. Most images are from cells grown in serum-free media for ~2 weeks... they make beautiful processes!

Microtubules & GFAP dominate in thick long primary processes.

And we see a novel actin structure - reticular webbing!

2/x

Wow! Good eye! You’re the only one who spotted the 5th chick 🤓

Dang where’s the 5th chick? I could only spot 4 in the picture though there were 6 chicks total.

Important work Teddy!