RhoGDIβ-induced hypertrophic growth and cell migration is Rac1-dependent, but suppression of cell cycle progression is not. (A) Control H9c2 and H9c2 RhoGDIβ-expressing cells stably transfected with Rac1, Rac1N17, or Rac1V12 were grown in 10% fetal bovine serum with doxycycline for three days, and the cell size was determined. (B) Wound-healing assay. The cell lines were seeded on plates, as previously described. After reaching confluency, the cell layer was wounded with a 200 μl pipette tip and incubated for 48 h with medium and doxycycline. (C) SiRNA knockdown of RhoGDIβ inhibited RhoGDIβ-induced Rac1 expression levels in H9c2 cells. U6-Ci is the scramble control siRNA, and both U6-353i and U6-568i are two specific RhoGDIβ siRNAs.