Importin-β negatively regulates multiple aspects of mitosis including RANGAP1 recruitment to kinetochores

• DOI: 10.1083/jcb.201109104
• Publication Date: 2012-02-14T05:10:01Z
• Authors: Emanuele Roscioli; Laura Di Francesco; Alessio Bolognesi; Maria Giubettini; Serena Orlando; Amnon Harel; Maria Eugenia Sch...; Patrizia Lavia
• Keywords: Importin; Nucleoporin; Ran; Nuclear pore

Importin-β is the main vector for interphase nuclear protein import and plays roles after envelope breakdown. Here we show that importin-β regulates multiple aspects of mitosis via distinct domains interact with different classes proteins in human cells. The C-terminal region (which binds importin-α) inhibits mitotic spindle pole formation. central (harboring nucleoporin-binding sites) microtubule dynamic functions interaction kinetochores. interacts through this NUP358/RANBP2, which turn SUMO-conjugated RANGAP1 pores. We continues pore disassembly. Overexpression importin-β, or region, inhibited recruitment to kinetochores, an event known require attachment exportin CRM1. Co-expressing either importin-β-interacting RANBP2 fragments, CRM1, restored kinetochores rescued importin-β-dependent defects. These results reveal previously unrecognized at exerted opposed by