Figure 6.

Stabilization of septin filaments or septin depletion impairs NK cell degranulation. (A–C) NKL cells were treated with 75 µM and (D–F) primary NK cells with 100 µM FCF for 3 h. (A and D) FCF-treated cells were activated with PMA (2 µM) and ionomycin (4 µM) for 30 min at 37°C in the presence of anti-CD107a antibody. Surface expression of CD107a was measured using FC. (B, C, E, and F) Percentage of CD107a and MFI of CD107a expression were quantified. (G) Primary NK cells were nucleofected with control or septin 7 siRNA. 48 h after nucleofection, levels of septin 7 protein were assessed by immunoblot. (H–J) Nucleofected cells were activated with PMA (2 µM) and ionomycin (4 µM) for 30 min at 37°C in the presence of anti-CD107a antibody. Surface expression of CD107a was measured using FC, and percentages of CD107a and MFI of CD107a expression were quantified. Results shown are the representative of three independent experiments, each performed in triplicate. Error bars indicate SEM. **, P < 0.005; ***, P < 0.0005 compared with control group. P values indicated are for paired, two-tailed Student’s t test. SSC-A, side scatter area.