The deduced 767-amino acid protein has a central proline-rich region and 4 C-terminal SH3 domains. PCR analysis detected EBP expression in all adult and fetal tissues examined. Epitope-tagged EBP was evenly distributed in the cytoplasm of transfected HeLa cells.

EBP was recruited to the nucleus by the chimeric MLL-EEN fusion protein. The SH3 domains of EBP interacted with SOS2, but not SOS1, and that the EBP-EEN and EBP-SOS2 interactions occurred simultaneously. Coexpression of EBP with EEN in rat embryonic fibroblasts led to suppression of RAS -induced cellular transformation and RAS-mediated activation of ELK1 .