EIF4EBP1 (eukaryotic translation initiation factor 4E binding protein 1, 4EBP1) is a translation repressor protein that directly interacts with eukaryotic translation initiation factor 4E (eIF4E), a limiting component of the multisubunit complex that recruits 40S ribosomal subunits to the 5' end of mRNAs. EIF4EBP1 interaction with eIF4E inhibits complex assembly and represses translation. It plays an important role in mTOR signaling. Furthermore, it is phosphorylated in response to various signals including UV irradiation and insulin signaling. In hepatocellular carcinoma, overexpression of this protein is correlated with progression and poor prognosis. In immunohistochemistry of normal tissue, EIF4EBP1 has cytoplasmic positivity in the salivary gland, pancreas, non-keratinized squamous epithelia and the gastrointestinal tract, as well as with a few other tissues throughout the body. References: PLoS One. 2015; 10(2): e0117493, PMID: 25658620; The UniProt Consortium. Nucleic Acids Res. 47: D506-515 (2019); Nucleic Acids Res. 2016 Jan 4;44(D1):D733-45, PMID:26553804;