EIF3D is a multifunctional translation initiation factor that serves dual roles as both a canonical subunit of the eIF3 complex and a non-canonical cap-binding protein 1. As part of the eIF3 complex, EIF3D participates in standard cap-dependent translation initiation 1. However, its most distinctive function involves mediating alternative cap-dependent translation when eIF4E is inactive. Under stress conditions that inactivate eIF4E, EIF3D directly binds mRNA caps through its cap-binding domain and enables continued translation of specific mRNA subsets 2 3. EIF3D also functions as a key regulator of the integrated stress response by controlling translation of stress response genes including GCN2 and ATF4 4. The protein demonstrates critical roles in maintaining cellular homeostasis across multiple contexts, including pluripotent stem cell maintenance 5, lipid metabolism regulation 6, and chr22 accessibility modulation 7. Disease relevance includes involvement in cancer progression through regulation of ferroptosis-related genes 8 and contribution to tumor survival under metabolic stress 6. EIF3D represents a crucial cellular survival mechanism that enables selective protein synthesis during stress conditions when canonical translation machinery is compromised.