Eukaryotic translation initiation factor 3 subunit H

Eukaryotic translation initiation factor 3 subunit H (eIF3H) is a 352-amino-acid component of the eIF-3 complex required for multiple steps in protein synthesis initiation (UniProt: O15372). It associates with the 40S ribosomal subunit to facilitate recruitment of initiation factors and formation of the 43S pre-initiation complex, while also regulating mRNA scanning for start codon recognition and ribosome recycling after translation termination.

eIF3H participates in selective translation of mRNAs governing cell proliferation, including genes involved in cell cycling, differentiation, and apoptosis. The eIF-3 complex employs distinct RNA stem-loop binding mechanisms to modulate translation of these target transcripts. No baseline disease associations are curated in UniProt for this protein.

In Alzheimer's disease, eIF3H is significantly up-regulated in post-mortem AD brain tissue compared to age-matched controls, with a mean log2 fold-change of +0.45 across two subcellular fractions in a TMT-based quantitative proteomics study of four subcellular compartments (Chaparral AD proteomics). This elevation suggests altered translational control may contribute to AD pathophysiology.