Kinesin-6

Kinesin-6 family members are microtubule-based motor proteins critical for cell division, including spindle assembly and chromosome segregation^[1][2][3]. Mechanistically, Kinesin-6 proteins, such as Subito in Drosophila or Klp9 in fission yeast, localize to the central spindle and spindle midzone during metaphase and anaphase, facilitating interpolar microtubule organization and spindle elongation^[1][4][3]. These motors interact with regulatory proteins including Polo, Incenp, and Aurora B, which are essential for proper cytokinesis and checkpoint signaling^[1][4]. Compared with related isoforms, single-molecule Kinesin-6 motors exhibit mostly non-processive behavior, but multi-motor ensembles can generate sufficient force to transport organelles and drive microtubule gliding^[2][3]. Functional studies of mutants reveal that Kinesin-6 deficiency results in misaligned or lagging chromosomes, spindle defects, and synthetic lethality when combined with other spindle assembly mutations, demonstrating both redundancy and specificity within mitotic pathways^[1][3]. Domain-swap experiments indicate that the tail domain primarily dictates cellular localization, the head domain contributes to microtubule binding and sliding forces, and the neck modulates force transmission, collectively distinguishing Kinesin-6 from other kinesin family members^[3]. For experimental applications, Kinesin-6’s differential processivity and domain-dependent activity provide a basis for dissecting spindle mechanics and testing motor-driven force regulation in mitotic models^[2][3].