Acetylation and activation of STAT3 mediated by nuclear translocation of CD44

AZ521/Mock and AZ521/CD44 cells were transfected to express both the Flag- and HA-tagged STAT3(WT), STAT3(K685R), STAT3(Y705F) or STAT3(K685R,Y705F). Nuclear extracts were prepared and subjected to tandem immunoprecipitation by anti-Flag followed by anti-HA. Left panel shows anti-Flag immunoprecipitates analyzed by western blotting for Flag-tagged STAT3, middle panel shows anti-HA immunoprecipitates analyzed for HA-tagged STAT3, and right panel shows anti-HA immunoprecipitates analyzed by western blotting for CD44.