tokens: Transient expression of actively mutated Fyn , having Phe-528 instead of Tyr-528 or Thr-338 instead of Ile-338 , in Jurkat T-cells stimulated the serum response element ( SRE ) , 12-O-tetradecanoyl-phorbol-13-acetate response element , cyclic AMP response element , and c-fos promoter .