A TAGLN2 knockout leads to diminished F-actin content and F-actin ring formation, resulting in lowered cell spreading and LFA-1–mediated conjugation formation. (A) T cells from TAGLN2^+/+ and TAGLN2^−/− mice were loaded on anti-CD3/28–coated coverslips for the indicated time points. Images shown are representative of three independent experiments. Cell spreading area and the percentages of actin rings were measured, as shown in Fig. 2 (A and B). R, ring; P, partial. Bar, 10 μm. (B) Relative F-actin content was measured as in Fig. 2 C. KO, knockout. (C) Mouse CD3⁺ T cells were mixed with SEB-loaded B cells, and conjugate formation for the indicated time points was determined as in Fig. 3 A. (D) BCECF-labeled mouse CD3⁺ T cells were preincubated for 30 min with or without 2 µM Cyt D, and then, adhesion to mICAM-1Fc in response to anti-CD3/28 was determined by measuring fluorescence intensity. All graphical results represent means ± SD of triplicate experiments. *, P < 0.05. T, TAGLN2; C, cofilin.