Treatment of mTEC-KO cells with a TβRI inhibitor and a ROCK inhibitor together, but not individually, reverses the mesenchymal actin cytoskeleton stress fibers induced by TGF-β1. mTEC-KO cells were incubated with 100 pM TGF-β1 for 72 hours, kinase inhibitors were added, and incubation was continued for an additional 24 hours. F-actin was visualized by staining with Texas Red-phalloidin. mTEC-KO cells were (A) untreated or treated with (B) 100 pM TGF-β1 for 72 hours followed by (C-G) single kinase inhibitor or (H-K) SB431542 plus a second kinase inhibitor. Single kinase inhibitors and concentrations were as follows: (C) 5 μM SB431542, (D) 1 μM SB203580, (E) 1 μM Y27632, (F) 10 μM U0126, and (G) 15 μM SP600125. Combinations of kinase inhibitors were 5 μM SB431542 with (H) 1 μM SB203580, (I) 1 μM Y27632, (J) 10 μM U0126, or (K) 15 μM SP600125. (L) Combination of 5 μM Y27632 and 5 μM SB203580. White arrows point to stress fibers.