ErbB3-binding protein 1 (EBP1)

ErbB3-binding protein 1 (EBP1) is a multifunctional, evolutionarily conserved protein encoded by the PA2G4 gene, existing as two main splice isoforms (p48 and p42) that differ by 54 amino acids at the N-terminus[2][5][7]. EBP1 was originally identified as an ErbB3-interacting protein (though only the p42 isoform binds ErbB3), and functions as a transcriptional and translational regulator, impacting eukaryotic cell growth, proliferation, apoptosis, and differentiation[1][2][5]. It plays roles in both transcription repression—by direct promoter binding and interference with epigenetic modifiers like DNMT1 and Suv39H1—and translation, through the regulation of ribosome and RNA interaction[1][2][5]. Isoforms have context-dependent roles: p48 EBP1 primarily acts oncogenically (enhancing proliferation and suppressing apoptosis), whereas p42 EBP1 acts as a tumor suppressor (promoting ubiquitin-proteasome-mediated degradation of PI3K p85, inhibiting PI3K/Akt signaling)[2][5][7]. EBP1 is essential for embryonic development: global loss leads to severe defects and apoptosis in early organs and the brain[2]. EBP1 is found to be overexpressed in several cancers, where its functional balance may influence tumor behavior and therapy response[5][6]. There are no major approved drugs directly targeting EBP1, and its functional duality and developmental roles pose safety concerns for therapeutic modulation[5][7].

Other names

PA2G4Ebp1ErbB3-binding protein 1proliferation-associated 2G4

Transcriptional repression (for some isoforms); Regulation of translation via interaction with mRNA/ribosome; Modulation of PI3K/Akt and p53 pathways via protein interaction