Microtubule-binding myosin required for nuclear anchoring and spindle assembly

Department of Zoology, University of Wisconsin, Madison, Madison, Wisconsin 53706, USA.
Nature (Impact Factor: 41.46). 10/2004; 431(7006):325-9. DOI: 10.1038/nature02834
Source: PubMed


Proper spindle positioning and orientation are essential for asymmetric cell division and require microtubule-actin filament (F-actin) interactions in many systems. Such interactions are particularly important in meiosis, where they mediate nuclear anchoring, as well as meiotic spindle assembly and rotation, two processes required for asymmetric cell division. Myosin-10 proteins are phosphoinositide-binding, actin-based motors that contain carboxy-terminal MyTH4 and FERM domains of unknown function. Here we show that Xenopus laevis myosin-10 (Myo10) associates with microtubules in vitro and in vivo, and is concentrated at the point where the meiotic spindle contacts the F-actin-rich cortex. Microtubule association is mediated by the MyTH4-FERM domains, which bind directly to purified microtubules. Disruption of Myo10 function disrupts nuclear anchoring, spindle assembly and spindle-F-actin association. Thus, this myosin has a novel and critically important role during meiosis in integrating the F-actin and microtubule cytoskeletons.

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    • "Myo VII contains a pair of MyTH4-FERM tandem domains, the second FERM domain of the Drosophila Myo VIIa binds to actin at high density (Yang et al., 2009). Unlike Myo VII, the MyTH-FERM tandem of Myo X, but not either of the isolated domains, was shown to bind to MTs (Weber et al., 2004; Kerber and Cheney, 2011) and also binds its cargo proteins, including β-integrins and the axonal guidance receptor DCC (Zhang et al., 2004; Zhu et al., 2007; Wei et al., 2011). Interestingly, in Drosophila myosin XV Sisyphus, the MyTH4 domain binds to MTs, whereas the FERM domain binds to various cargos including the MT-severing protein, Katanin p60 subunit (Liu et al., 2008). "
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    • "in cytoskeleton , MTs and their regulated interplay are required for successful chromosome segregation ( Rodriguez et al . , 2003 ; Woolner et al . , 2008 ) . Recent studies demonstrated that myosin - 10 is an essential integrator of spindle MTs with cortical F - actin required for nuclear anchoring and spindle assembly in Xenopus laevis oocytes ( Weber et al . , 2004 ) . Other examples include the association of nonmuscle myosin - 2 ( MHC - A ) with MTs of the spindle apparatus ( Kelley et al . , 1996 ) and the localization of myosin - 5 at the MT organizing center during melanocyte cell division ( Wu et al . , 1998 ) . Diffusive interactions of myosin - 5 with MTs are assumed to be required for eff"

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    • "Disruption of Factin in Xenopus embryos also leads to spindle mispositioning in the outer epithelial cells (Woolner et al., 2008). Unconventional myosin-X, which binds both to microtubules and actin (Hirano et al., 2011; Weber et al., 2004), is required for spindle orientation in cultured cells (Toyoshima and Nishida, 2007). Indeed, a study of epithelial cells of Xenopus embryos shows that myosin-X and F-actin both contribute to the anchoring of the spindle at the cortex (Woolner et al., 2008). "
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