Eukaryotic translation initiation factor 3 subunit A

EIF3A encodes the A subunit of eukaryotic translation initiation factor 3 (eIF-3), an RNA-binding component essential for multiple steps in translation initiation. The protein facilitates recruitment of initiation factors to the 40S ribosomal subunit, promotes mRNA scanning and AUG recognition, and regulates translation of specific mRNAs involved in cell proliferation, differentiation, and apoptosis (UniProt: Q14152). EIF3A is also required for viral translation initiation on certain IRES elements.

EIF3A functions as a core component of the eIF-3 complex, which operates at the early stages of protein synthesis across diverse cell types. The protein has no annotated disease associations in the UniProt record.

In Alzheimer's Disease, EIF3A is upregulated in post-mortem AD brain tissue compared to age-matched controls, with a mean log2 fold-change of +0.61 (Chaparral AD proteomics). This upregulation was detected across one fraction in a TMT-labeled quantitative proteomics study of four subcellular fractions from human brain samples, suggesting potential dysregulation of translation initiation machinery in AD pathology.