The nuclear F‐actin interactome of Xenopus oocytes reveals an actin‐bundling kinesin that is essential for meiotic cytokinesis |
| |
| Authors: | Matthias Samwer Heinz‐Jürgen Dehne Felix Spira Martin Kollmar Daniel W Gerlich Henning Urlaub Dirk Görlich |
| |
| Institution: | 1.Department of Cellular Logistics, MPI for Biophysical Chemistry, Göttingen, Germany;2.Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna, Austria;3.Systems Biology of Motor Proteins Group, MPI for Biophysical Chemistry, Göttingen, Germany;4.Bioanalytical Mass Spectrometry Group, MPI for Biophysical Chemistry, Göttingen, Germany |
| |
| 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. |
| |
| Keywords: | cytokinesis kinesins meiosis nuclear actin phalloidin |
|
|
