The divergent mitotic kinesin MKLP2 exhibits atypical structure and mechanochemistry.

Joseph Atherton,Yannick Sourigues,Joseph M Muretta,I-Mei Yu,Carolyn A Moores,Jennifer Major,Anne Houdusse,Agnel Joseph,Alexander Cook,Jeffrey Clause,Maya Topf,Steven S Rosenfeld

doi:10.7554/elife.27793

Abstract

MKLP2, a kinesin-6, has critical roles during the metaphase-anaphase transition and cytokinesis. Its motor domain contains conserved nucleotide binding motifs, but is divergent in sequence (~35% identity) and size (~40% larger) compared to other kinesins. Using cryo-electron microscopy and biophysical assays, we have undertaken a mechanochemical dissection of the microtubule-bound MKLP2 motor domain during its ATPase cycle, and show that many facets of its mechanism are distinct from other kinesins. While the MKLP2 neck-linker is directed towards the microtubule plus-end in an ATP-like state, it does not fully dock along the motor domain. Furthermore, the footprint of the MKLP2 motor domain on the MT surface is altered compared to motile kinesins, and enhanced by kinesin-6-specific sequences. The conformation of the highly extended loop6 insertion characteristic of kinesin-6s is nucleotide-independent and does not contact the MT surface. Our results emphasize the role of family-specific insertions in modulating kinesin motor function.

Highlights

The success of mitosis depends on the intricate timing, precise localisation and regulated interactions between multiple spindle components
MKLP2 is required for localisation of Chromosome Passenger Complex (CPC) components, including Aurora B kinase, to the midzone at anaphase (Gruneberg et al, 2004), which is in turn required for Kif4A and PRC1 function (Nunes Bastos et al, 2013)
While the cell biological contributions of MKLP2 and other kinesin-6s during mitosis are increasingly well understood, little has been known about the molecular mechanism of these divergent mitotic motors

Summary

Introduction

The success of mitosis depends on the intricate timing, precise localisation and regulated interactions between multiple spindle components. MKLP2 is required for localisation of Chromosome Passenger Complex (CPC) components, including Aurora B kinase, to the midzone at anaphase (Gruneberg et al, 2004), which is in turn required for Kif4A and PRC1 function (Nunes Bastos et al, 2013). MKLP2 participates in myosin II recruitment for cleavage furrow ingression (Kitagawa et al, 2013) and interacts with the cell membrane to promote abscission (Fung et al, 2017). It is a substrate for polo-like kinase 1 (Plk1), and the co-association at the midzone of MKLP2 and Plk is required for cytokinesis (Neef et al, 2003). While there has been significant focus on dissecting cell cycle dependent

Methods

Results

Conclusion