Targeting EBF2 condensates modulates adipose thermogenesis

Brown adipose tissue (BAT) actively dissipates energy and represents a promising therapeutic target for combating obesity. The establishment of the thermogenic gene program is orchestrated by the pioneering transcription factor Early B Cell Factor 2 (EBF2). Here, we identified a low-complexity C-terminal domain (CTD) within EBF2 that drives biomolecular condensation and is essential for thermogenic activation. Deletion of the CTD (EBF2 ΔCTD) or mutation of key proline residues within this region did not affect the genomic binding of EBF2, but profoundly impaired its ability to undergo phase separation and to drive brown adipocyte differentiation and thermogenic function both in vitro and in vivo. Fusion of the intrinsic disorder region (IDR) of FUS to EBF2 ΔCTD fully restored its function, whereas fusion with MED1-IDR resulted in distinct phenotypic outcomes. Mechanistically, EBF2 formed condensates with ZFP423, a key repressor of brown adipocyte differentiation. This co-condensation excluded HDAC1 from the complex, establishing a permissive chromatin environment that promotes active transcription. Furthermore, a phase separation-based phenotypic drug screen identified compounds that modulated EBF2 condensate formation and thermogenic genes expression. Our findings reveal phase separation as an emerging regulatory mechanism underlying brown fat determination and suggest that targeting biomolecular condensation offers a novel therapeutic strategy for obesity.