Cell contraction induced by ARHGEF10 ΔN in HEK293T cells. A, domain structures of ARHGEF10 are presented. Full-length ARHGEF10 (wt) and an N-terminal truncation mutant lacking N-terminal 332 amino acids of ARHGEF10 (ΔN) are shown. B, HEK293T cells were transiently transfected with the plasmid encoding GFP, GFP-tagged ARHGEF10 wt, or GFP-ARHGEF10 ΔN. After 48 h, fluorescence images of living cells were observed. Scale bar, 10 μm. C, quantitative analysis of cell contraction of HEK293T cells is shown. HEK293T cells were transiently transfected with the plasmid encoding GFP, GFP-ARHGEF10 wt or ΔN. The proportion of cell contraction was scored as a percentage of the rounded cells of GFP-positive cells. Cells floating in the culture medium were excluded from counting. The data represent the mean ± S.E. (error bars) from three independent experiments. *, p < 0.05 compared with empty. For each experiment, >100 cells were counted. D, HEK293T cells were transiently transfected with the plasmid encoding GFP-ARHGEF10 wt or ΔN. After 48 h, cells were fixed and co-stained with TRITC-phalloidin (F-actin) and Hoechst33258 (DNA). Transfected cells are shown by the fluorescence of GFP. Scale bar, 10 μm.