SASH1 and cancer: Furthermore, IFITM4P acts as a scaffold to facilitate recruitment of SASH1 to bind and phosphorylate TAK1 (Thr187) and further increase the phosphorylation of NF-κB (Ser536) to directly induce PD-L1 transcription, thus activating an immunosuppressive program that allows OL and OSCC cells to escape anti-cancer immunity in the cytoplasm.