TAF7 accumulates in the cytoplasm during cellular transformation and engages STAT3, WASH, and CCT.

TAF7, a core subunit of the general transcription factor TFIID, regulates transcription and additionally functions as an RNA chaperone that directs nascent nuclear RNAs to cytoplasmic polysomes, thereby influencing protein synthesis. Here, we identify a set of novel cytoplasmic interactors and a previously unappreciated cytoplasmic role for TAF7 in oncogenesis. BioID-mediated proximity labeling identified STAT3 and the CCT and WASH complexes as prominent cytoplasmic interactors of TAF7. These interactions were validated by co-immunoprecipitation and proximity ligation assays. We further showed that cytoplasmic TAF7 levels increased during oncogenesis in proportion to cancer cell pathogenicity. Notably, TAF7 engagement with STAT3, CCT and WASH complexes is markedly enhanced during cellular transformation, consistent with their functions in cancer progression. Together, these findings reveal a cytoplasmic TAF7 interactome and implicate elevated cytoplasmic TAF7 as associated with oncogenesis.