Molecular mechanisms of IKKα nuclear transportation. Ran GTPase activity is required for the nuclear transport of IKKα through interacting with importin-α. In response to HBx overexpression and cisplatin treatment, phosphorylations of IKKα at Thr23 and Ser473 by Akt and ATM respectively promote its nuclear translocation. The ubiquitination of IKKα is essential for the Akt-regulated IKKα nuclear import. Under exposure to ROS, activated PKCδ also enhances the nuclear accumulation of IKKα.