title: Allosteric inhibition of kinesin-5 modulates its processive directional motility.
abstract: Small-molecule inhibitors of kinesin-5 (refs. 1-3), a protein essential for eukaryotic cell division, represent alternatives to antimitotic agents that target tubulin. While tubulin is needed for multiple intracellular processes, the known functions of kinesin-5 are limited to dividing cells, making it likely that kinesin-5 inhibitors would have fewer side effects than do tubulin-targeting drugs. Kinesin-5 inhibitors, such as monastrol, act through poorly understood allosteric mechanisms, not competing with ATP binding. Moreover, the microscopic mechanism of full-length kinesin-5 motility is not known. Here we characterize the motile properties and allosteric inhibition of Eg5, a vertebrate kinesin-5, using a GFP fusion protein in single-molecule fluorescence assays. We find that Eg5 is a processive kinesin whose motility includes, in addition to ATP-dependent directional motion, a diffusive component not requiring ATP hydrolysis. Monastrol suppresses the directional processive motility of microtubule-bound Eg5. These data on Eg5's allosteric inhibition will impact these inhibitors' use as probes and development as chemotherapeutic agents.
authors.affiliation: Laboratory of Chemistry and Cell Biology, The Rockefeller University, 1230 York Avenue, New York, New York 10021, USA.
authors.forename: Benjamin H
authors.initials: BH
authors.lastname: Kwok
authors.forename: Lukas C
authors.initials: LC
authors.lastname: Kapitein
authors.forename: Jeffrey H
authors.initials: JH
authors.lastname: Kim
authors.forename: Erwin J G
authors.initials: EJ
authors.lastname: Peterman
authors.forename: Christoph F
authors.initials: CF
authors.lastname: Schmidt
authors.forename: Tarun M
authors.initials: TM
authors.lastname: Kapoor
mesh_terms: D000494:Allosteric Regulation; D000818:Animals; D050256:Antimitotic Agents / Q000494:pharmacology; D049452:Green Fluorescent Proteins / Q000378:metabolism; D016547:Kinesins / Q000037:antagonists & inhibitors*; D008856:Microscopy, Fluorescence; D008870:Microtubules / Q000187:drug effects / Q000378:metabolism*; D011743:Pyrimidines / Q000494:pharmacology; D011993:Recombinant Fusion Proteins / Q000378:metabolism*; D008941:Spindle Apparatus / Q000187:drug effects / Q000378:metabolism*; D013871:Thiones / Q000494:pharmacology; D029867:Xenopus Proteins / Q000037:antagonists & inhibitors*; D014982:Xenopus laevis
chemical_list: D050256:Antimitotic Agents; C088335:KIF11 protein, Xenopus; D011743:Pyrimidines; D011993:Recombinant Fusion Proteins; D013871:Thiones; D029867:Xenopus Proteins; D049452:Green Fluorescent Proteins; C400223:monastrol; D016547:Kinesins