SWAP‐70 is important for invasive phenotypes of mouse embryo fibroblasts transformed by v‐Src

SWAP‐70 is a protein involved in actin rearrangement, especially in membrane ruffling. Mouse embryo fibroblasts (MEFs) deficient in SWAP‐70 show impaired membrane ruffling and fail to grow in soft agar after transformation by v‐Src. Here, we show that v‐Src transformed MEFs expressing SWAP‐70 are highly invasive. MEFs expressing SWAP‐70 or v‐Src alone were far less invasive, suggesting that both proteins were required for the cells to be invasive. Expression of both SWAP‐70 and v‐Src induced constant membrane ruffling, which may cause vigorous cell movement, probably required for invasiveness of the cells. Expression of v‐Src alone morphologically transformed MEFs but formed lamellipodia rather than membrane ruffles, suggesting less aggressive nature of the cells compared with those expressing both SWAP‐70 and v‐Src. These results suggest that v‐Src and SWAP‐70 act synergistically in the invasion activity of MEFs. © 2008 IUBMB IUBMB Life, 60(4): 236–240, 2008