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Reposted by Griffiths Lab

Journal of Cell Science @jcellsci.bsky.social · 10/09/2025

New JCS snapshot - Cytotoxic T lymphocytes adapt to the loss of Cdc42 @adamrochussen.bsky.social presents the key findings from their recent JCS paper with Claire Ma and Gillian Griffiths @griffithslab.bsky.social. journals.biologists.com/jcs/article/...

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Griffiths Lab @griffithslab.bsky.social · 04/08/2025

If you find a difference in phenotype between knockout and inhibitor/knockdown, transcriptional adaptation may be the culprit. This remarkable phenomenon demonstrates the robustness & complexity of cells, but can hamper CRISPR-based investigations if you aren't aware of it! doi.org/10.1242/jcs....

doi.org

Transcriptional adaptation after deletion of Cdc42 in primary T cells

Highlighted Article: CRISPR/Cas9-mediated deletion of Cdc42 in primary T cells triggers transcriptional adaptation, leading to enhanced T cell function. Chemical inhibition with CASIN is highly specif...

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Griffiths Lab @griffithslab.bsky.social · 04/08/2025

This phenomenon is called "transcriptional adaptation", as coined by @stainierlab.bsky.social Consistent with their NMD-mediated mechanism, we found targeting the promoter of Cdc42 avoids TA in CTLs. It also seems to be specific for CDC42 among Rho GTPases in CTLs.

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Griffiths Lab @griffithslab.bsky.social · 04/08/2025

Multi-omics revealed that the knockout cells were compensating for the loss of CDC42 by transcriptionally upregulating genes that could enhance T cell function, including by upregulating the activity of related Rho GTPases!

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Griffiths Lab @griffithslab.bsky.social · 04/08/2025

CRISPR/Cas9-mediated gene deletion normally requires several days of recovery before assaying cellular function. When we performed killing assays daily after delivery of RNPs, we found that the knockout cells initially pheno-copied inhibited cells, but then regained functionality over time

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Griffiths Lab @griffithslab.bsky.social · 04/08/2025

Inhibiting CDC42 with a chemical inhibitor (CASIN) gave the opposite result: worsened CTL function. Meanwhile, the knockout cells showed *enhanced* function regardless of inhibitor treatment ...

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Griffiths Lab @griffithslab.bsky.social · 04/08/2025

Confusingly, we found the knockout cells performed *better* than control cells across killing, degranulation, migration, and signalling.

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Griffiths Lab @griffithslab.bsky.social · 04/08/2025

CDC42 is a Rho GTPase known to control cell polarity and cytoskeletal dynamics in many cell types. It is necessary for embryonic viability in mice, and pathogenic variants cause immunodeficiency diseases in humans. To determine its role in CTLs, we targeted the Cdc42 gene via CRISPR/Cas9

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Griffiths Lab @griffithslab.bsky.social · 04/08/2025

Sometimes, knocking out a gene isn't a good way to figure out the function of that gene ... In our new @jcellsci.bsky.social paper, we report potent transcriptional adaptation by cytotoxic T lymphocytes (CTLs) in response to CRISPR/Cas9-mediated deletion of the important polarity protein CDC42 🧵⬇️

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Griffiths Lab @griffithslab.bsky.social · 17/01/2025

As promised at my seminar at NCBS, here is the video showing what happens to the centrosome in a “confused T cell” that is contacting two targets with equal signals.

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Griffiths Lab @griffithslab.bsky.social · 08/01/2025

You're seeing the actin cytoskeleton of cytotoxic T lymphocytes as they crawl across glass. These guys move at around 0.15 μm/s. Movie taken by PhD student @adamrochussen.bsky.social on our spinning disk confocal microscope.

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Griffiths Lab @griffithslab.bsky.social · 08/01/2025

Welcome to the dynamic world of T cells!

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