Expression and translocation of YopN-GSK. Translocation and phosphorylation of YopN-GSK in infected HeLa cells. Infected HeLa cell monolayers were solubilized with SDS-PAGE sample buffer and analyzed by SDS-PAGE in a 12.5% polyacrylamide gel and immunoblotted. Immunoblots were probed with phospho-GSK-3β antibodies that detect the GSK tag only when phosphorylated and α-YopN antibodies. Proteins were visualized by probing with alkaline phosphatase conjugated secondary antibodies and developed with NBT-BCIP.