MYH14 and melanoma: We next tested whether these RhoGEFs had unique functions impacting actomyosin contractility as a marker for invasive capacity as was previously reported.13,16,17,46,52 Using A375M2 amoeboid metastatic melanoma cells seeded on collagen we confirmed that individual RNAi depletion of these three GEFs had no effects on morphology (Fig. 2d, e; cells grown on collagen) and myosin activity (pMLC2; Fig. 2f).