title: Xenopus laevisKif18A is a highly processive kinesin required for meiotic spindle integrity.
abstract: The assembly and functionality of the mitotic spindle depends on the coordinated activities of microtubule-associated motor proteins of the dynein and kinesin superfamily. Our current understanding of the function of motor proteins is significantly shaped by studies usingXenopus laevisegg extract as its open structure allows complex experimental manipulations hardly feasible in other model systems. Yet, the Kinesin-8 orthologue of human Kif18A has not been described inXenopus laevisso far. Here, we report the cloning and characterization ofXenopus laevis(Xl) Kif18A.XenopusKif18A is expressed during oocyte maturation and its depletion from meiotic egg extract results in severe spindle defects. These defects can be rescued by wild-type Kif18A, but not Kif18A lacking motor activity or the C-terminus. Single-molecule microscopy assays revealed that Xl_Kif18A possesses high processivity, which depends on an additional C-terminal microtubule-binding site. Human tissue culture cells depleted of endogenous Kif18A display mitotic defects, which can be rescued by wild-type, but not tail-less Xl_Kif18A. Thus, Xl_Kif18A is the functional orthologue of human Kif18A whose activity is essential for the correct function of meiotic spindles inXenopusoocytes.
authors.affiliation: Department of Molecular Genetics and Konstanz Research School Chemical Biology, University of Konstanz, Universitätsstraße 10, Konstanz 78457, Germany.
authors.forename: Martin M
authors.initials: MM
authors.lastname: Möckel
authors.affiliation: Department of Molecular Genetics and Konstanz Research School Chemical Biology, University of Konstanz, Universitätsstraße 10, Konstanz 78457, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Heim
authors.affiliation: Department of Molecular Genetics and Konstanz Research School Chemical Biology, University of Konstanz, Universitätsstraße 10, Konstanz 78457, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Tischer
authors.affiliation: Department of Molecular Genetics and Konstanz Research School Chemical Biology, University of Konstanz, Universitätsstraße 10, Konstanz 78457, Germany Thomas.U.Mayer@uni-konstanz.de.
authors.forename: Thomas U
authors.identifier: http://orcid.org/0000-0001-6954-2287
authors.initials: TU
authors.lastname: Mayer
keywords: Kif18A; Kinesin-8; Meiosis; Spindle structure; Xenopus laevis