Models for KIF4A function chromosome alignment and anaphase spindle formation. (A) The model summarizes Aurora-regulated kinetochore-dependent and -independent pathways contributing to chromosome congression. At kinetochores, Aurora B destabilizes kinetochore–microtubule attachments for nonbioriented chromosomes. Aurora A phosphorylates the condensin I–bound pool of KIF4A at polar chromosomes, promoting KIF4A motor activity and chromosome congression. (B) In anaphase, PRC1 and KIF4A control microtubule growth and the organization of the anaphase spindle, ensuring symmetric furrowing. The KIF4A mutant FF1154AA shows this interaction is essential for regulated microtubule growth and organized cytokinesis.