Importin-5

Importin-5 (IPO5) is a nuclear transport receptor that mediates the nuclear import of cargo proteins bearing nuclear localization signals (NLS) (UniProt: O00410). It functions by binding substrate proteins, docking the complex to the nuclear pore, and facilitating translocation through a Ran-GTP-dependent mechanism. The protein has documented roles in importing ribosomal proteins (RPL23A, RPS7, RPL5), histones, and the neuronal protein CPEB3 following stimulation.

Importin-5 is broadly expressed and participates in fundamental nucleocytoplasmic transport pathways essential to cell homeostasis. No specific tissue-restricted function or non-neurological disease association is noted in UniProt curated records.

In Alzheimer's disease, Importin-5 shows ambiguous directional change across subcellular fractions in post-mortem AD brain proteomics (Chaparral AD proteomics). The mean log2 fold-change relative to age-matched controls is 0.1745 across two fractions, indicating minimal net shift in abundance. This modest variation may reflect altered subcellular localization or compartment-specific differences rather than robust dysregulation, suggesting Importin-5 is not a major candidate in the AD proteome signature.