A microtubule-binding myosin required for nuclear anchoring and spindle assembly

  title={A microtubule-binding myosin required for nuclear anchoring and spindle assembly},
  author={Kari L. Weber and Anna Marie Sokac and Jonathan S. Berg and Richard E. Cheney and William M. Bement},
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… 

Myosin-10 and actin filaments are essential for mitotic spindle function

It is found that Myo10 localizes to mitotic spindle poles and is essential for proper spindle anchoring, normal spindle length, spindle pole integrity, and progression through metaphase.

Myosin-1C associates with microtubules and stabilizes the mitotic spindle during cell division

The data reveal that myosin-1C binds to MTs and has a role in maintenance of spindle stability for accurate chromosome separation, and shows that the association of myosIn1C with MTs is mediated through the tail domain.

Myosin-X is dispensable for spindle morphogenesis and positioning in the mouse oocyte

It is shown that myosin-X is not localized on the spindle, and is dispensable for spindle and F-actin assembly, and it is not required for force transmission as spindle migration and chromosome alignment occur normally.

Mitotic spindle perturbations

It is demonstrated that Plk1 is a negative regulator of cortical LGN, a key recruitment factor of dynein, and that the kinetochore-pool of Plk 1 on misaligned chromosomes delocalizes LGN from cortical sites in its proximity, thereby inducing spindle misorientation.

The myosin regulatory light chain Myl5 localizes to mitotic spindle poles and is required for proper cell division

It is determined that the previously uncharacterized myosin RLC Myl5 associates with the mitotic spindle and is required for cell division.

Spindle–F-actin interactions in mitotic spindles in an intact vertebrate epithelium

It is concluded that there is a robust endoplasmic F-actin network in normal vertebrate epithelial cells and that this network is also a component of mitotic spindles.

Fission yeast Myo51 is a meiotic spindle pole body component with discrete roles during cell fusion and spore formation

It is shown that Myo51 has an important role in regulating spore formation upon completion of meiosis, and is dependent on a stable microtubule cytoskeleton and the presence of the Cdc2-CyclinB complex.

LIM Kinase-mediated Cofilin Phosphorylation during Mitosis Is Required for Precise Spindle Positioning*

It is shown that mitotic LIMK1 activation is critical for accurate spindle orientation in mammalian cells and suggested that LIMK 1-mediated cofilin phosphorylation is required for accurateSpindle orientation by stabilizing cortical actin networks during mitosis.



A Class VI Unconventional Myosin Is Associated with a Homologue of a Microtubule-binding Protein, Cytoplasmic Linker Protein–170, in Neurons and at the Posterior Pole of Drosophila Embryos

The association of a myosin and a homologue of a microtubule-binding protein in the nervous system and at the posterior pole, leads us to speculate that these two proteins may functionally link the actin and microtubules cytoskeletons.

Myosin-Va binds to and mechanochemically couples microtubules to actin filaments.

Results demonstrate that myosin-Va is a microtubule binding protein that cross-links and mechanochemically couples microtubules to actin filaments.

Direct interaction of microtubule- and actin-based transport motors

It is shown that an actin-based vesicle-transport motor, MyoVA, can interact directly with a microtubule-based transport motor, KhcU, indicating that cellular transport is, in part, coordinated through the direct interaction of different motor molecules.

Cdc42-dependent actin polymerization during compensatory endocytosis in Xenopus eggs

4D microscopy is used to visualize the contribution of actin during compensatory endocytosis in Xenopus laevis eggs and shows that the actin cytoskeleton maintains exocytosing cortical granules as discrete invaginated compartments, such that when actin is disrupted, they collapse into the plasma membrane.

F-actin is required for spindle anchoring and rotation in Xenopus oocytes: a re-examination of the effects of cytochalasin B on oocyte maturation

Treatment with CB during maturation disrupted the normal organisation of the novel MTOC and transient microtubule array (MTOC-TMA complex) that serves as the immediate precursor of the first meiotic spindle, suggesting that F-actin plays an important role in the assembly or maintenance of this complex.

The distribution and requirements of microtubules and microfilaments in bovine oocytes during in vitro maturation

It is suggested that both microtubules and microfilaments are closely associated with reconstruction and proper positioning of chromatin during meiotic maturation in bovine oocytes.

Motor Function and Regulation of Myosin X*

The results suggest that myosin X is a nonprocessive motor, and ADP did not significantly inhibit the actin-activated ATPase activity of myOSin X, suggesting that the ADP release step is not rate-limiting.

Regulation of Melanosome Movement in the Cell Cycle by Reversible Association with Myosin V

It is shown that organelle transport by myosin V is controlled by a cell cycle-regulated association of this motor to organelles, and that this binding is likely regulated by phosphorylation of myos in V during mitosis.