13. Even when we used a non-signalling CAR mutant, CD45 was still excluded at protrusions.
So the enhanced CD45 exclusion is not signalling-dependent.

12. We observed that exclusion at protrusion contacts happened earlier and more strongly when compared to CD45 exclusion at flat membranes

8. Then comes LAT, clustering downstream of ZAP-70.
LAT clusters appear faster and more intensely in protrusions compared to main body membrane regions

7. The CAR clusters are activated immediately and the increased CAR enrichment in protrusions is accompanied with an increased ZAP-70 recruitment to these structures

5. In collaboration with Amin from the @ewerslab.bsky.social, we developed an image analysis pipeline to distinguish between protrusions and main body protein rearrangements

4. The logic works both ways: protrusive structures from the breast cancer cell are also able to push into the T cell and create a contact that accumulates CARs!

3. But the game changes when T cells meet their targets.
First contacts happen via protrusions.
Within seconds, CARs cluster specifically at these sites. In here, you can see a Jurkat T cell expressing a HER2-CAR (yellow) and a membrane marker (cyan) contacting a breast cancer cell (magenta).