FIG. 8.
The stability of YopE influences the activities of YopP and YopH. (A) Effect of YopE on YopP-dependent inactivation of p38. HEK293 cells were left untreated or infected with WA, WA-ΔyopP, WA-YopEwt, or WA-YopEK62R/K75Q. Cellular lysates were prepared 4 h after onset of infection, and the phosphorylation and activation status of the MAPK p38 was assessed by immunoblotting with an antibody that recognizes active p38 phosphorylated at T180/Y182. (B) Effect of YopE on YopH-dependent inhibition of p130Cas phosphorylation. HEK293 cells were left untreated or infected the YopH-deficient mutant WA-ΔyopH, WA-YopEwt, or WA-YopEK62R/K75Q. Cellular lysates were prepared after 3.5 h of infection, and phosphorylation of p130Cas was assessed by immunoblotting with an antibody recognizing Y249-phosphorylated p130Cas. The total pools of p38 and p130Cas in the cell lysates for panels A and B were controlled by reprobing the membranes with general anti-p38 and anti-p130Cas antibody, respectively. The phosphorylation of p130Cas in relation to total p130Cas was quantified by densitometry. Values are expressed as percentages of p130Cas phosphorylation relative to infection with WA-ΔyopH (100%) and the background immunoblot signal (0%).