title: The nuclear F-actin interactome of Xenopus oocytes reveals an actin-bundling kinesin that is essential for meiotic cytokinesis.
abstract: Nuclei of Xenopus laevis oocytes grow 100 000-fold larger in volume than a typical somatic nucleus and require an unusual intranuclear F-actin scaffold for mechanical stability. We now developed a method for mapping F-actin interactomes and identified a comprehensive set of F-actin binders from the oocyte nuclei. Unexpectedly, the most prominent interactor was a novel kinesin termed NabKin (Nuclear and meiotic actin-bundling Kinesin). NabKin not only binds microtubules but also F-actin structures, such as the intranuclear actin bundles in prophase and the contractile actomyosin ring during cytokinesis. The interaction between NabKin and F-actin is negatively regulated by Importin-β and is responsive to spatial information provided by RanGTP. Disconnecting NabKin from F-actin during meiosis caused cytokinesis failure and egg polyploidy. We also found actin-bundling activity in Nabkin's somatic paralogue KIF14, which was previously shown to be essential for somatic cell division. Our data are consistent with the notion that NabKin/KIF14 directly link microtubules with F-actin and that such link is essential for cytokinesis.
authors.affiliation: Department of Cellular Logistics, MPI for Biophysical Chemistry, Göttingen, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Samwer
authors.forename: Heinz-Jürgen
authors.initials: HJ
authors.lastname: Dehne
authors.forename: Felix
authors.initials: F
authors.lastname: Spira
authors.forename: Martin
authors.initials: M
authors.lastname: Kollmar
authors.forename: Daniel W
authors.initials: DW
authors.lastname: Gerlich
authors.forename: Henning
authors.initials: H
authors.lastname: Urlaub
authors.forename: Dirk
authors.initials: D
authors.lastname: Görlich
mesh_terms: D000199:Actins / Q000378:metabolism*; D000205:Actomyosin / Q000378:metabolism; D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism*; D002846:Chromatography, Affinity; D048749:Cytokinesis / Q000502:physiology*; D005260:Female; D005455:Fluorescent Antibody Technique; D015151:Immunoblotting; D016547:Kinesins / Q000378:metabolism*; D008540:Meiosis / Q000502:physiology*; D008870:Microtubules / Q000378:metabolism; D009865:Oocytes / Q000166:cytology / Q000378:metabolism*; D010590:Phalloidine / Q000378:metabolism; D011003:Ploidies; D040901:Proteomics; D011994:Recombinant Proteins / Q000378:metabolism; D053719:Tandem Mass Spectrometry; D014982:Xenopus laevis / Q000254:growth & development / Q000378:metabolism*
chemical_list: D000199:Actins; D011994:Recombinant Proteins; D010590:Phalloidine; D000205:Actomyosin; D016547:Kinesins