title: A kinesin-13 mutant catalytically depolymerizes microtubules in ADP.
abstract: The kinesin-13 motor protein family members drive the removal of tubulin from microtubules (MTs) to promote MT turnover. A point mutation of the kinesin-13 family member mitotic centromere-associated kinesin/Kif2C (E491A) isolates the tubulin-removal conformation of the motor, and appears distinct from all previously described kinesin-13 conformations derived from nucleotide analogues. The E491A mutant removes tubulin dimers from stabilized MTs stoichiometrically in adenosine triphosphate (ATP) but is unable to efficiently release from detached tubulin dimers to recycle catalytically. Only in adenosine diphosphate (ADP) can the mutant catalytically remove tubulin dimers from stabilized MTs because the affinity of the mutant for detached tubulin dimers in ADP is low relative to lattice-bound tubulin. Thus, the motor can regenerate for further cycles of disassembly. Using the mutant, we show that release of tubulin by kinesin-13 motors occurs at the transition state for ATP hydrolysis, which illustrates a significant divergence in their coupling to ATP turnover relative to motile kinesins.
authors.affiliation: Deptartment of Physiology and Biophysics, University of Washington School of Medicine, Seattle, WA 98107, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Wagenbach
authors.forename: Sarah
authors.initials: S
authors.lastname: Domnitz
authors.forename: Linda
authors.initials: L
authors.lastname: Wordeman
authors.forename: Jeremy
authors.initials: J
authors.lastname: Cooper
mesh_terms: D000244:Adenosine Diphosphate / Q000235:genetics / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000235:genetics / Q000378:metabolism; D019943:Amino Acid Substitution; D000818:Animals; D002417:Cattle; D002460:Cell Line; D019281:Dimerization; D006801:Humans; D006868:Hydrolysis; D016547:Kinesins / Q000235:genetics / Q000378:metabolism*; D008870:Microtubules / Q000235:genetics / Q000378:metabolism*; D020125:Mutation, Missense; D014404:Tubulin / Q000235:genetics / Q000378:metabolism*
chemical_list: C091489:KIF2C protein, human; D014404:Tubulin; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D016547:Kinesins