To elucidate the role of individual components of Rho/ROCK/MLC signaling in the amoeboid invasiveness of sarcoma cells, cell lines were prepared to stably express either GFP-tagged dnRhoA (A3dnRho; inactivating mutation T19N) or GFP-tagged non-phosphorylable (dominant negative) MLC (A3dnMLC; mutations T18A, S19A) in A3 cells. Here, MLC1 is linked to sarcoma.