title: A second tubulin binding site on the kinesin-13 motor head domain is important during mitosis.
abstract: Kinesin-13s are microtubule (MT) depolymerases different from most other kinesins that move along MTs. Like other kinesins, they have a motor or head domain (HD) containing a tubulin and an ATP binding site. Interestingly, kinesin-13s have an additional binding site (Kin-Tub-2) on the opposite side of the HD that contains several family conserved positively charged residues. The role of this site in kinesin-13 function is not clear. To address this issue, we investigated the in-vitro and in-vivo effects of mutating Kin-Tub-2 family conserved residues on the Drosophila melanogaster kinesin-13, KLP10A. We show that the Kin-Tub-2 site enhances tubulin cross-linking and MT bundling properties of KLP10A in-vitro. Disruption of the Kin-Tub-2 site, despite not having a deleterious effect on MT depolymerization, results in abnormal mitotic spindles and lagging chromosomes during mitosis in Drosophila S2 cells. The results suggest that the additional Kin-Tub-2 tubulin biding site plays a direct MT attachment role in-vivo.
authors.affiliation: Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, New York, United States of America ; State Key Lab of Reproductive Medicine, College of Basic Medicine, Nanjing Medical University, Nanjing, Jiangsu, China.
authors.forename: Dong
authors.initials: D
authors.lastname: Zhang
authors.forename: Ana B
authors.initials: AB
authors.lastname: Asenjo
authors.forename: Michaela
authors.initials: M
authors.lastname: Greenbaum
authors.forename: Luping
authors.initials: L
authors.lastname: Xie
authors.forename: David J
authors.initials: DJ
authors.lastname: Sharp
authors.forename: Hernando
authors.initials: H
authors.lastname: Sosa
mesh_terms: D000818:Animals; D001665:Binding Sites / Q000502:physiology; D002460:Cell Line; D029721:Drosophila Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster; D016547:Kinesins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008870:Microtubules / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008938:Mitosis / Q000502:physiology*; D009154:Mutation; D017434:Protein Structure, Tertiary; D014404:Tubulin / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D029721:Drosophila Proteins; D014404:Tubulin; C481339:KLP10A protein, Drosophila; D016547:Kinesins