FIG. 7.

Akt is activated in 208F cells transformed by JSRV or ENTV Env tyrosine mutants, as determined by Akt phosphorylation at Ser473 (pAkt) and in vitro kinase assay (pGSK-3α/β). Experimental procedures were the same as those described in Fig. 3, except that the cell lysates were obtained from 208F cells transformed by several tyrosine mutants of JSRV and ENTV Env. 208F cells transformed by the parental JSRV (Jenv-FLAG) or ENTV (FLAG-Eenv) Env proteins served as positive controls. The lower panel shows Env expression in the cell lysates by immunoblotting with the anti-FLAG antibody. Similar results were also obtained for all other ENTV and JSRV Env tyrosine mutants, and all experiments were performed at least three times.