Eukaryotic translation initiation factor 3 subunit J

EIF3J encodes eukaryotic translation initiation factor 3 subunit J (eIF3j), a 258-amino acid component of the eIF-3 complex required for multiple steps in protein synthesis initiation (UniProt: O75822). The eIF-3 complex associates with the 40S ribosome to facilitate recruitment of initiation factors, promote mRNA binding and scanning, and regulate ribosomal recycling. The complex selectively controls translation of mRNAs involved in cell proliferation, differentiation, and apoptosis through RNA stem-loop interactions that enable either activation or repression.

EIF3J participates in the core translation machinery and is expressed across tissues. UniProt reports no curated disease associations in its knowledge base for this protein.

In Alzheimer's disease, EIF3J is upregulated in human post-mortem AD brain relative to age-matched controls (Chaparral AD proteomics: mean log2FC = 0.189), based on TMT-labeled tandem mass spectrometry analysis of four subcellular fractions. This elevation may reflect compensatory or dysregulated translational responses in the AD brain proteome, though the biological significance requires further investigation.