Taf14 recognizes a common motif in transcriptional machineries and facilitates their clustering by phase separation

Saccharomyces cerevisiae TBP associated factor 14 (Taf14) is a well-studied transcriptional regulator that controls diverse physiological processes and that physically interacts with at least seven nuclear complexes in yeast. Despite multiple previous Taf14 structural studies, the nature of its disparate transcriptional regulatory functions remains opaque. Here, we demonstrate that the extra-terminal (ET) domain of Taf14 (Taf14(ET)) recognizes a common motif in multiple transcriptional coactivator proteins from several nuclear complexes, including RSC, SWI/SNF, INO80, NuA3, TFIID, and TFIIF. Moreover, we show that such partner binding promotes liquid-liquid phase separation (LLPS) of Taf14(ET), in a mechanism common to YEATS-associated ET domains (e.g., AF9(ET)) but not Bromo-associated ET domains from BET-family proteins. Thus, beyond identifying the molecular mechanism by which Taf14(ET) associates with many transcriptional regulators, our study suggests that Taf14 may function as a versatile nuclear hub that orchestrates transcriptional machineries to spatiotemporally regulate diverse cellular pathways.S. cerevisiae TBP associated factor 14 (Taf14) is a transcriptional regulator that interacts with multiple nuclear complexes. Here, the authors report that the extra-terminal domain of Taf14 (Taf14(ET)) recognizes a common motif in various transcriptional coactivator proteins and they solve the NMR structure of Taf14(ET) bound the ET-binding motif of Sth1, the catalytic subunit of the RSC (Remodel the Structure of Chromatin) complex, and furthermore show that Taf14(ET) undergoes liquid-liquid phase separation, which is enhanced by Taf14 interaction partners.