TEAD/TEF transcription factors utilize the activation domain of YAP65, a Src/Yes-associated protein localized in the cytoplasm

Mammals express four highly conserved TEAD/TEF transcription factors that b ind the same DNA sequence, but serve different functions during development . TEAD-2/TEF-4 protein purified from mouse cells was associated predominant ly with a novel TEAD-binding domain at the amino terminus of YAP65, a power ful transcriptional coactivator. YAP65 interacted specifically with the car boxyl terminus of all four TEAD proteins. Both this interaction and sequenc e-specific DNA binding by TEAD were required for transcriptional activation in mouse cells. Expression of YAP in lymphocytic cells that normally do no t support TEAD-dependent transcription (e.g., MPC11) resulted in up to 300- fold induction of TEAD activity. Conversely, TEAD overexpression squelched YAP activity. Therefore, the carboxy-terminal acidic activation domain in Y AP is the transcriptional activation domain for TEAD transcription factors. However, whereas TEAD was concentrated in the nucleus, excess YAP65 accumu lated in the cytoplasm as a complex with the cytoplasmic localization prote in, 14-3-3. Because TEAD-dependent transcription was limited by YAP65, and YAP65 also binds Src/Yes protein tyrosine kinases, we propose that YAP65 re gulates TEAD-dependent transcription in response to mitogenic signals.