Alfredo Sciortino
@asciortino.bsky.social
Biophysicist / cytoskeleton in vitro
🏙 Paris @CytoMorphoLab
🏙 Paris @CytoMorphoLab
You know the pain 🥰 gracias
February 26, 2025 at 12:36 PM
You know the pain 🥰 gracias
So.. thanks for reading! I hope you liked it - and check out the preprint. Also thanks to @manuelthery.bsky.social and @lblanchoin.bsky.social , to Magali in particular, and to all coauthors (I think only @alexandra-colin.bsky.social is here..)! www.biorxiv.org/content/10.1...
www.biorxiv.org
February 26, 2025 at 9:13 AM
So.. thanks for reading! I hope you liked it - and check out the preprint. Also thanks to @manuelthery.bsky.social and @lblanchoin.bsky.social , to Magali in particular, and to all coauthors (I think only @alexandra-colin.bsky.social is here..)! www.biorxiv.org/content/10.1...
So yes: filaments transport in 3D allows to separate a contractile flux at the bottom of the well with an extensile flux pushing filaments back to the periphery through the network's 3D architecture.
February 26, 2025 at 9:13 AM
So yes: filaments transport in 3D allows to separate a contractile flux at the bottom of the well with an extensile flux pushing filaments back to the periphery through the network's 3D architecture.
If the DSS is through filament transport in 3D then severing those bundles in the middle of the well should stop it. So we performed laser ablation and *zap* the bundles are gone and the DSS contracts and dies out.
February 26, 2025 at 9:13 AM
If the DSS is through filament transport in 3D then severing those bundles in the middle of the well should stop it. So we performed laser ablation and *zap* the bundles are gone and the DSS contracts and dies out.
Well apparently yes! The network uses its 3D architecture to "suck" filaments at the center and "inject" them back at the periphery - again, we show this with tracking filaments in 3D. But it's barely visible in the data, so we developed a killer experiment ;-) go to the next block to see it..
February 26, 2025 at 9:13 AM
Well apparently yes! The network uses its 3D architecture to "suck" filaments at the center and "inject" them back at the periphery - again, we show this with tracking filaments in 3D. But it's barely visible in the data, so we developed a killer experiment ;-) go to the next block to see it..
Well, if it is not nucleation and it is not transport in 2D, we might as well take a look at the network architecture in 3D! Using confocal we observe this weird tent-like structure - is it possible that filaments are transported through it?
February 26, 2025 at 9:13 AM
Well, if it is not nucleation and it is not transport in 2D, we might as well take a look at the network architecture in 3D! Using confocal we observe this weird tent-like structure - is it possible that filaments are transported through it?
What we find is that transport on the wells surface is coherent with actomyosin sliding combined with some "gliding" due to motors sticking to the membrane. But the net flux is still contractile, so what is pushing filaments back to the periphery...???
February 26, 2025 at 9:13 AM
What we find is that transport on the wells surface is coherent with actomyosin sliding combined with some "gliding" due to motors sticking to the membrane. But the net flux is still contractile, so what is pushing filaments back to the periphery...???
It's not actin turnover, the classical answer: this DSS works in the absence of actin nucleators or in the presence of phalloidin, i.e. with stabilized filaments. No depolymerization is present. So it has to be transport of the filaments. We combine a bunch of techniques to observe it, like speckle.
February 26, 2025 at 9:13 AM
It's not actin turnover, the classical answer: this DSS works in the absence of actin nucleators or in the presence of phalloidin, i.e. with stabilized filaments. No depolymerization is present. So it has to be transport of the filaments. We combine a bunch of techniques to observe it, like speckle.
... and we got this: continuous actin contraction for hours and hours without collapse to the center. We also show how the flow and the actin architecture are organized in space in a regular way.
The question is... what is sustaining this dynamic state? What "compensates" for this contractile flow?
The question is... what is sustaining this dynamic state? What "compensates" for this contractile flow?
February 26, 2025 at 9:13 AM
... and we got this: continuous actin contraction for hours and hours without collapse to the center. We also show how the flow and the actin architecture are organized in space in a regular way.
The question is... what is sustaining this dynamic state? What "compensates" for this contractile flow?
The question is... what is sustaining this dynamic state? What "compensates" for this contractile flow?