Heterogeneous nuclear ribonucleoprotein A3

Heterogeneous nuclear ribonucleoprotein A3 (hnRNP A3) is an RNA-binding protein encoded by HNRNPA3 that plays a role in cytoplasmic trafficking of RNA and binds to A2RE cis-acting response elements; it may also participate in pre-mRNA splicing (UniProt: P51991). The protein is expressed in the brain and functions within pathways governing post-transcriptional gene regulation and RNA localization.

In Alzheimer's Disease, hnRNP A3 shows ambiguous regulation across subcellular fractions in human post-mortem AD brain tissue compared to age-matched controls, as measured by TMT-labeled quantitative proteomics across four subcellular fractions (P2, P3, S2, S3) (Chaparral AD proteomics). The mean log2 fold-change is −0.4606, indicating modest downregulation overall, though directional consistency varied across fractions. This pattern suggests altered subcellular localization or compartment-specific changes rather than uniform protein loss in AD pathology.