G, H, Overexpression of OTUB1 has no effect on serum-induced MAPK activation in cell expressing mutant NRAS Q61K or KRAS G12V. Whole cell lysates were analyzed by immunoblotting using antibodies as indicated. A,B,C,D,E,F,G,H Serum-starved HEK293T cells expressing the indicated constructs were stimulated with 10% serum for the indicated time periods. 