Phospho-eIF4E (Ser209) Recombinant Rabbit mAb (S-2652-195)

Phospho-eIF4E (Ser209) refers to the activated form of the eukaryotic translation initiation factor 4E following the phosphorylation of its serine residue at position 209. This event is a critical regulatory step in controlling the initiation of protein synthesis. eIF4E itself is the key initiation factor that recognizes and binds to the 5' cap structure of mRNA, serving as the core component of the eIF4F complex responsible for recruiting the ribosome to the mRNA. When its Ser209 site is phosphorylated by the specific kinases MNK1 and MNK2, the affinity of eIF4E for the cap structure is significantly enhanced, and its binding to eIF4G is promoted. This process preferentially accelerates the translation efficiency of a specific class of mRNAs, which typically possess highly complex 5' untranslated regions and encode proteins crucial for cell proliferation, survival, migration, and angiogenesis (such as c-Myc, Cyclin D1, and VEGF). This phosphorylation event is a key downstream effect of the Ras/MAPK signaling pathway. Notably, in cancer, the level of Phospho-eIF4E (Ser209) is often abnormally elevated, leading to increased synthesis of oncogenic proteins that drive tumor initiation, progression, invasion, and resistance to chemotherapy. Consequently, it is regarded as a highly promising therapeutic target and prognostic biomarker in oncology.