Anti-KPNA3

KPNA3 (karyopherin alpha 3), also known as importin alpha 4, is a member of the importin alpha family of proteins which includes KPNA1 (importin alpha 5), KPNA2 (importin alpha 1), KPNA3 (importin alpha 4), KPNA4 (importin alpha 3), KPNA5 (importin alpha 6), and KPNA6 (importin alpha 7). The importin alpha family of proteins plays a role in the import of proteins from the cytoplasm to the nucleus. The import of proteins from the cytoplasm to the nucleus involves docking the protein to receptors associated with the nuclear pore complex (NPC) followed by translocation through the nuclear pore. Importin alpha proteins bind the nuclear localization signal (NLS) of cargo proteins and function as adaptor proteins for the nuclear pore receptor KPNB1 (importin beta 1). KPNB1 is responsible for docking the importin-cargo complex to the cytoplasmic side of the NPC for its translocation through the NPC. KPNA3 (Importin alpha 4) and KPNA4 (importin alpha 3) have been reported to mediate the nuclear import of TNF-alpha induced nuclear import of NF-kappaB p50/p65 heterodimers. KPNA3 has also been reported to be responsible for the ligand-independent nuclear translocation of the vitamin D receptor. Protein function: Functions in nuclear protein import as an adapter protein for nuclear receptor KPNB1. Binds specifically and directly to substrates containing either a simple or bipartite NLS motif. Docking of the importin/substrate complex to the nuclear pore complex (NPC) is mediated by KPNB1 through binding to nucleoporin FxFG repeats and the complex is subsequently translocated through the pore by an energy requiring, Ran-dependent mechanism. At the nucleoplasmic side of the NPC, Ran binds to importin-beta and the three components separate and importin-alpha and -beta are re-exported from the nucleus to the cytoplasm where GTP hydrolysis releases Ran from importin. The directionality of nuclear import is thought to be conferred by an asymmetric distribution of the GTP- and GDP-bound forms of Ran between the cytoplasm and nucleus. In vitro, mediates the nuclear import of human cytomegalovirus UL84 by recognizing a non-classical NLS. Recognizes NLSs of influenza A virus nucleoprotein probably through ARM repeats 7-9. [The UniProt Consortium]