E1F4EBP1 (eukaryotic translation initiation factor 4E binding protein 1) is involved in protein synthesis, cell growth and survival. In unphosphorylated form, it suppresses the translation initiation of capped mRNAs. On the other hand, in phosphorylated form, it increases translation initiation. Phosphorylation of E1F4EBP1 releases it from eIF4E (eukaryotic translation initiation factor 4E), thereby resulting in cap-dependent translation. E1F4EBP1 is also involved in tumorigenesis and the gene is overexpressed in various carcinomas. It is also a substrate for mTORC1 (mammalian target of rapamycin complex 1). In non-phosphorylated conditions, it interacts with p21 (cyclin-dependent kinase inhibitor) and enhances destabilization of p21.
