Eukaryotic translation initiation factor 5

Eukaryotic translation initiation factor 5 (eIF5) is a core component of the 43S pre-initiation complex that regulates ribosomal scanning and start codon recognition during translation (UniProt: P55010). It acts as a GTPase-activating protein for eIF2G, promoting GTP hydrolysis and coordinating interactions between eIF1 and eIF1A to maintain the open conformation of the scanning complex until the initiation codon is located.

In human cells, eIF5 functions during the early, rate-limiting steps of translation initiation. The protein stabilizes the pre-initiation complex and facilitates the conformational transitions necessary for accurate start codon selection, making it essential for translational fidelity and efficiency.

EIF5 is upregulated in Alzheimer's Disease brain tissue compared to age-matched controls, with a mean log2 fold-change of +0.30 detected across post-mortem AD samples analyzed by quantitative proteomics (Chaparral AD proteomics). This modest elevation suggests a potential role in the translational remodeling observed in AD pathophysiology, possibly reflecting altered protein synthesis patterns associated with neurodegeneration.