Fig. 2.

Distinct actin cytoskeleton dynamics in primary and immortalised T-cells. (A) Kymographs comparing F-actin-expressing live mouse (Lifeact-GFP, white arrows) and Jurkat CD4⁺ T-cells (Lifeact-citrine) at the basal membrane within 3 min after contact with the activating SLB with and without fluorescent label of anti-CD3-Alexa-568 (red arrow). (B) Kymographs comparing live mouse and Jurkat CD4⁺ T-cells expressing F-actin show immobile F-actin features (white arrows), dynamic F-actin (blue arrows), and distinct leading edges in live mouse and Jurkat CD4⁺ T-cells (red arrows). (C) Representative tracking of the TCR over time in live mouse CD4⁺ T-cells expressing F-actin (Lifeact-GFP) with early-to-late time-points scaled in cold-to-warm colours. (D) Quantification of actin and TCR flow velocities for multiple experimental conditions. No quantitative differences were observed in the TCR flow velocities (ns, P>0.9) across experimental conditions as well as comparing between primary mouse CD4⁺ and Jurkat CD4⁺ T-cells (ns, P>0.9). In contrast, quantitative differences were observed in actin flow velocities (**P<0.001) under experimental conditions as well as when comparing primary mouse CD4⁺ and Jurkat CD4⁺ T-cells (**P<0.001). Further details are provided in the text. Scale bars: 1 μm (A,B), 5 μm (C).