Expression of NRAS (K61) in MDCK cells. MDCK cells were transfected with 3 μg of pCDNA3.1 (+)-NRAS (K61). At 36 h posttransfection, cells were collected and lysed in SDS-PAGE gel loading buffer. Protein was detected by Western blotting by using N-ras-specific monoclonal antibody F155. A clear band could be seen in the blot.