Immunofluorescence analysis of Phospho-STAT3 (Ser727) was performed using 90% confluent log phase NIH/3T3 cells treated with IL6 (100 ng/mL, 30 mins). The cells were fixed with 4% paraformaldehyde for 10 minutes, permeabilized with 0.1% Triton™ X-100 for 15 minutes, and blocked with 1% BSA for 1 hour at room temperature. The cells were labeled with Phospho-STAT3 (Ser727) Polyclonal Antibody (Product # PA5-17876) at 1:100 in 0.1% BSA, incubated at 4 degree Celsius overnight and then labeled with Goat anti-Rabbit IgG (H+L) Superclonal™ Secondary Antibody, Alexa Fluor® 488 conjugate (Product # A27034) at a dilution of 1:2000 for 45 minutes at room temperature (Panel a: green). Nuclei (Panel b: blue) were stained with SlowFade® Gold Antifade Mountant with DAPI (Product # S36938). F-actin (Panel c: red) was stained with Rhodamine Phalloidin (Product # R415, 1:300). Panel d represents the merged image showing nuclear localization. Panel e represents untreated cells. Panel f represents control cells with no primary antibody to assess background. The images were captured at 60X magnification.