Importin-beta family

The **Importin-beta family** (also called **Karyopherin-beta family**) comprises a group of nuclear transport receptors responsible for shuttling proteins and RNAs across the nuclear envelope via nuclear pore complexes[1][5][6][9]. Members of this family can function as importins (importing cargos into the nucleus) or exportins (exporting cargos from the nucleus) and are regulated by the small GTPase Ran[5][6]. Importin-beta itself, the prototype, binds to nuclear localization sequences directly or acts in concert with importin-alpha as an adaptor[1][7][8]. Family members recognize different cargoes and mediate distinct yet sometimes overlapping transport pathways involved in cell cycle, signal transduction, gene expression, and chromatin organization[2][9]. Dysfunction or abnormal regulation of certain importin-beta family members has been linked to cancer, viral infection, and neurodegenerative conditions. Therapeutic targeting faces challenges due to the essential housekeeping roles of these transporters and their broad substrate specificity, but inhibitors have been developed in research settings to probe their function or interfere with viral replication. The family consists of multiple isoforms, with at least 22 members in humans, and exhibits considerable diversity in tissue expression and cargo selectivity[6][9].

Other names

Importin-β familyKaryopherin-β familyImportin betaKaryopherin betaImportin subunit betaKaryopherins

Inhibition of nuclear import of target proteins by blocking importin-β/cargo or importin-β/nucleoporin interaction Disruption of nuclear pore transport