A SWI/SNF-specific Ig-like domain, SWIFT, is a transcription factor binding platform

Mammalian SWI/SNF (BAF) chromatin remodeling complexes modulate DNA accessibility and gene expression, however, the mechanisms by which these master regulatory complexes are targeted on chromatin remain incompletely understood. Here, we define SWIFT (SWI/SNF Ig-Fold for Transcription Factor Interactions) found on the SMARCD family of subunits within the core module as a transcription factor (TF) binding platform. We demonstrate that SWIFT is necessary and sufficient for direct interaction with the transactivation domain of a lineage-specific TF, PU.1, in vitro and in cells. A single amino acid mutation in SWIFT disrupts the PU.1-mSWI/SNF interaction, inhibits site-specific complex targeting and activity, and attenuates oncogenic gene expression and proliferation of PU.1-dependent AML cells. Dominant expression of SWIFT in isolation sequesters mSWI/SNF-interacting TFs and poisons TF-addicted cancer cells. Finally, we present SWIFT as an evolutionarily conserved domain that serves as a universal binding platform for diverse TFs, suggesting approaches for modulation of cell type and disease-specific transcription.