HDACIs reduce the levels of Rho-GTPase family members in murine fetal liver–derived megakaryocytes and the human megakaryoblastic cell line Meg-01. (A) Western blot performed on fetal liver cell–derived megakaryocytes treated for 48 hours with 10nM panobinostat (Pan) and 1nM romidepsin (Romi) showing a reduction in CDC42, Rac1, and RhoA, but no change in PAK1 or ROCK1 levels. (B) Western blot performed on Meg-01 cells treated for 24 hours with 20nM panobinostat and 20nM romidepsin showing a reduction in CDC42, Rac1, and RhoA, but no change in PAK1 or ROCK1 levels.