EIF4E3 is a eukaryotic translation initiation factor that recognizes and binds the 7-methylguanosine (m7G) cap structure on mRNA 1, employing an atypical cap-binding mechanism distinct from other eIF4E family members 1. Unlike the canonical aromatic sandwich used by eIF4E1, EIF4E3 uses a unique spatial arrangement of residues to achieve electrostatic and van der Waals contacts with the m7G cap 1. Mechanistically, EIF4E3 localizes to stress granules upon cellular stress and interacts with eIF4G1, eIF4G3, and PABP1 to facilitate translation initiation 2. Under mTOR inhibition stress, EIF4E3 forms an active eIF4F complex (eIF4FS) that selectively translates specific mRNA populations based on 5' UTR length, functioning as a second branch of the integrated stress response 3. EIF4E3 may also act as a regulatory switch modulating eIF4E1-driven oncogenic translation in diffuse large B-cell lymphoma 4. Clinically, EIF4E3 exhibits tumor-suppressive functions through its cap-binding activity 1, with reduced expression observed in high eIF4E cancers. In head and neck squamous cell carcinoma, elevated EIF4E3 expression correlates with enhanced immune infiltration and improved immunotherapy response through CCL4/CCL5 regulation 5. EIF4E3 also emerges as a prognostic biomarker in breast cancer 6 and atrial fibrillation-related stroke 7, suggesting broad clinical relevance across multiple disease contexts.