title: Myosin-10 independently influences mitotic spindle structure and mitotic progression.
abstract: The iconic bipolar structure of the mitotic spindle is of extreme importance to proper spindle function. At best, spindle abnormalities result in a delayed mitosis, while worse outcomes include cell death or disease. Recent work has uncovered an important role for the actin-based motor protein myosin-10 in the regulation of spindle structure and function. Here we examine the contribution of the myosin tail homology 4 (MyTH4) domain of the myosin-10 tail to the protein's spindle functions. The MyTH4 domain is known to mediate binding to microtubules and we verify the suspicion that this domain contributes to myosin-10's close association with the spindle. More surprisingly, our data demonstrate that some but not all of myosin-10's spindle functions require microtubule binding. In particular, myosin-10's contribution to spindle pole integrity requires microtubule binding, whereas its contribution to normal mitotic progression does not. This is demonstrated by the observation that dominant negative expression of the wild-type MyTH4 domain produces multipolar spindles and an increased mitotic index, whereas overexpression of a version of the MyTH4 domain harboring point mutations that abrogate microtubule binding results in only the mitotic index phenotype. Our data suggest that myosin-10 helps to control the metaphase to anaphase transition in cells independent of microtubule binding. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Biology Department, Grinnell College, Grinnell, Iowa.|Department of Zoology, University of Wisconsin-Madison, Madison, Wisconsin.
authors.forename: Joshua C
authors.initials: JC
authors.lastname: Sandquist
authors.affiliation: Program in Cellular and Molecular Biology and the Medical Scientist Training Program, University of Wisconsin-Madison, Madison, Wisconsin.
authors.forename: Matthew E
authors.initials: ME
authors.lastname: Larson
authors.affiliation: Biology Department, Grinnell College, Grinnell, Iowa.
authors.forename: Ken J
authors.initials: KJ
authors.lastname: Hine
mesh_terms: D000705:Anaphase / Q000502:physiology*; D000818:Animals; D008677:Metaphase / Q000502:physiology*; D009218:Myosins / Q000235:genetics / Q000378:metabolism*; D000072417:Protein Domains; D008941:Spindle Apparatus / Q000201:enzymology* / Q000235:genetics; D029867:Xenopus Proteins / Q000235:genetics / Q000378:metabolism*; D014982:Xenopus laevis
chemical_list: C492069:Myo10 protein, Xenopus; D029867:Xenopus Proteins; D009218:Myosins
keywords: cytoskeleton; microtubule; mitosis; myosin; spindle