RT Journal Article SR Electronic T1 Kinesin-6 Klp9 orchestrates spindle elongation by regulating microtubule sliding and growth JF bioRxiv FD Cold Spring Harbor Laboratory SP 2021.02.17.431708 DO 10.1101/2021.02.17.431708 A1 Lara K. Krüger A1 Matthieu Gélin A1 Liang Ji A1 Carlos Kikuti A1 Anne Houdusse A1 Manuel Théry A1 Laurent Blanchoin A1 Phong T. Tran YR 2021 UL http://biorxiv.org/content/early/2021/02/18/2021.02.17.431708.abstract AB Mitotic spindle function depends on the precise regulation of microtubule dynamics and microtubule sliding. Throughout mitosis, both processes have to be orchestrated to establish and maintain spindle stability. We show that during anaphase B spindle elongation in S. pombe, the sliding motor Klp9 (kinesin-6) also promotes microtubule growth in vivo. In vitro, Klp9 can enhance and dampen microtubule growth, depending on the tubulin concentration. This indicates that the motor is able to promote and block tubulin subunit incorporation into the microtubule lattice in order to set a well-defined microtubule growth velocity. Moreover, Klp9 recruitment to spindle microtubules is dependent on its dephosphorylation mediated by XMAP215/Dis1, a microtubule polymerase, to link the regulation of spindle length and spindle elongation velocity. Collectively, we unravel the mechanism of anaphase B, from Klp9 recruitment to the motors dual-function in regulating microtubule sliding and microtubule growth, allowing an inherent coordination of both processes.