Anti-eIF4E (phospho S209) antibody (ab4774)

Immunofluorescence analysis using 70% confluent log phase U-87 MG cells labeled for Phospho-eIF4E pSer209 using ab4774. The cells were fixed with 4% paraformaldehyde for 10 minutes, permeabilized with 0.1% Triton™ X-100 for 10 minutes, and blocked with 1% BSA for 1 hour at room temperature. The cells were labeled with ab4774 at 1:250 dilution in 0.1% BSA and incubated for 3 hours at room temperature and then labeled with Goat anti-Rabbit IgG (H+L) Superclonal™ Secondary Antibody, Alexa Fluor® 488 conjugate 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. F-actin (Panel C: red) was stained with Rhodamine Phalloidin (1:300). Panel D is a merged image showing cytoplasmic localization. Panel E is a no primary antibody control. The images were captured at 60X magnification.

Western blot analysis was performed on HeLa, HEK-293 (human cell lines) and L6 (rat cell line) cell lysates with various treatments, blotted for eIF4E (pS209) using ab4774. Two bands ~ 25 and 28 kDa band corresponding to eIF4E (pS209) was observed across cell lines tested. Known quantity of protein samples were electrophoresed using Novex® NuPAGE® 12 % Bis-Tris gel, XCell SureLock™ Electrophoresis System and Novex® Sharp Pre-Stained Protein Standard. Resolved proteins were then transferred onto a nitrocellulose membrane with iBlot® 2 Dry Blotting System. The membrane was probed with the relevant primary and secondary Antibody following blocking with 5 % skimmed milk. Chemiluminescent detection was performed using Pierce™ ECL Western Blotting Substrate 

The data show that only the peptide corresponding to eIF4E (phospho S209) blocks the antibody signal, demonstrating the specificity of the antibody. The data also show that phosphatase stripping eliminates the signal, verifying that the antibody i