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ryan weeks

@ryanweeeeks.bsky.social
225 followers 881 following 10 posts

genetically encoded biosensors. Former UCSD looking at ras.

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ryan weeks @ryanweeeeks.bsky.social · 24/08/2026
Also big thanks to @michellefrei17.bsky.social who really made it possible, bringing the materials and knowledge for these tools to the lab. As well as Daojia (Rosie) Zhou who had really good ideas and work that moved the project!
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ryan weeks @ryanweeeeks.bsky.social · 24/08/2026
Happy to see this idea through and seeing the sensor in action! With further improvement--ideal packaging and cell line generation (or further optimization)--HaloRasAR may enable facile images of endogenous Ras activity!
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ryan weeks @ryanweeeeks.bsky.social · 24/08/2026
We think this spatially biased inhibition is due to BAY293-induced inhibition of wild-type isoforms—in MIA PaCa-2 this is the H/NRasWT isoforms with more prevalent Golgi localization.
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ryan weeks @ryanweeeeks.bsky.social · 24/08/2026
We did live cell pharmacology in MIA PaCa-2 cells testing out Ras inhibitors that use different mechanisms. Notably, when using GEF-inhibitor BAY293, we saw partial inhibition with bias towards the Golgi Apparatus, whereas the KRasG12C-targeting Ras(ON) RMC6291 showed plasma membrane bias.
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ryan weeks @ryanweeeeks.bsky.social · 24/08/2026
For example, striking responses were measured in HEK293t stably expressing HaloRasAR under Tet-inducible TRE3G promoter, with slight induction (100-500pg DOX). (Labelled with 25nM JF635).
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ryan weeks @ryanweeeeks.bsky.social · 24/08/2026
Endogenous Ras responses of HaloRasAR work well when its expression is tailored to low levels that better match the fluctuations of Ras activity at endogenous levels.
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ryan weeks @ryanweeeeks.bsky.social · 24/08/2026
We see a dynamic range of ~150% in vitro and ~130% in cells, and we can report endogenous Ras activity quite well.
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ryan weeks @ryanweeeeks.bsky.social · 24/08/2026
We fused the bright mNeonGreen n-terminally to ensure intensity-based fluctuations of J635 can be normalized against Ras-activity induced translocation. We measure the activity of HaloRasAR by far-red/green ratio.
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ryan weeks @ryanweeeeks.bsky.social · 24/08/2026
In this work we develop HaloRasAR, a chemigenetic biosensor capable of detecting endogenous Ras by fluorogenic increase in far-red fluorescence upon Ras interaction. The design implements circularly permuted self labelling protein HaloTag, labelled with Janelia Fluor dye JF635.
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ryan weeks @ryanweeeeks.bsky.social · 24/08/2026
Really excited to share the publication of my PhD work in the Jin Zhang lab at UCSD! You can find it here in Nature Chemical Biology. www.nature.com/articles/s41...
nature.com
A chemigenetic endogenous Ras activity biosensor for live-cell pharmacology - Nature Chemical Biology
Here the authors present a biosensor for measuring endogenous Ras in live cells, based on HaloTag and the fluorogenic JF635 dye, and they use it to report location-specific inhibition profiles of dist...
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