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Molecular basis of human kinesin-8 function and inhibition
Structural highlights
FunctionKI18A_HUMAN Microtubule-depolymerizing kinesin which plays a role in chromosome congression by reducing the amplitude of preanaphase oscillations and slowing poleward movement during anaphase, thus suppressing chromosome movements. May stabilize the CENPE-BUB1B complex at the kinetochores during early mitosis and maintains CENPE levels at kinetochores during chromosome congression.[1] [2] [3] [4] Publication Abstract from PubMedKinesin motors play diverse roles in mitosis and are targets for antimitotic drugs. The clinical significance of these motors emphasizes the importance of understanding the molecular basis of their function. Equally important, investigations into the modes of inhibition of these motors provide crucial information about their molecular mechanisms. Kif18A regulates spindle microtubules through its dual functionality, with microtubule-based stepping and regulation of microtubule dynamics. We investigated the mechanism of Kif18A and its inhibition by the small molecule BTB-1. The Kif18A motor domain drives ATP-dependent plus-end microtubule gliding, and undergoes conformational changes consistent with canonical mechanisms of plus-end-directed motility. The Kif18A motor domain also depolymerizes microtubule plus and minus ends. BTB-1 inhibits both of these microtubule-based Kif18A activities. A reconstruction of BTB-1-bound, microtubule-bound Kif18A, in combination with computational modeling, identified an allosteric BTB-1-binding site near loop5, where it blocks the ATP-dependent conformational changes that we characterized. Strikingly, BTB-1 binding is close to that of well-characterized Kif11 inhibitors that block tight microtubule binding, whereas BTB-1 traps Kif18A on the microtubule. Our work highlights a general mechanism of kinesin inhibition in which small-molecule binding near loop5 prevents a range of conformational changes, blocking motor function. Structural basis of human kinesin-8 function and inhibition.,Locke J, Joseph AP, Pena A, Mockel MM, Mayer TU, Topf M, Moores CA Proc Natl Acad Sci U S A. 2017 Oct 23. pii: 201712169. doi:, 10.1073/pnas.1712169114. PMID:29078367[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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