Article

The myosin superfamily at a glance

Department of Biochemistry, Stanford University, Stanford, CA 94305, USA.
Journal of Cell Science (Impact Factor: 5.43). 04/2012; 125(Pt 7):1627-32. DOI: 10.1242/jcs.094300
Source: PubMed
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    • "The remaining three encode the non-muscle (NM) myosin isoforms 2A, 2B, and 2C, which contribute to cell shape, adhesion, and cytokinesis (Mogilner and Keren, 2009; Vicente-Manzanares et al., 2009). Myosin isoforms in the remaining classes contribute to a wide range of functions, including organelle trafficking, membrane tethering, Golgi organization, actin organization, and actin polymerization (Hartman and Spudich, 2012). Individual cell types only express a subset of myosin genes. "
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    ABSTRACT: We investigated the myosin expression profile in prostate cancer cell lines and found that Myo1b, Myo9b, Myo10, and Myo18a were expressed at higher levels in cells with high metastatic potential. Moreover, Myo1b and Myo10 were expressed at higher levels in metastatic tumors. Using an siRNA-based approach, we found that knockdown of each myosin resulted in distinct phenotypes. Myo10 knockdown ablated filopodia and decreased 2D migration speed. Myo18a knockdown increased circumferential non-muscle myosin 2A-associated actin filament arrays in the lamella and reduced directional persistence of 2D migration. Myo9b knockdown increased stress fiber formation, decreased 2D migration speed, and increased directional persistence. Conversely, Myo1b knockdown increased numbers of stress fibers but did not affect 2D migration. In all cases, the cell spread area was increased and 3D migration potential was decreased. Therefore, myosins not only act as molecular motors but also directly influence actin organization and cell morphology, which can contribute to the metastatic phenotype.
    Full-text · Article · Dec 2015 · Cell Reports
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    • "Myosin VI is an ATP hydrolysis coupled motor protein involved in many cellular functions including endocytosis, protein secretion and the maintenance of both the Golgi morphology and stereocilia [1]. It is a unique myosin in that it moves to the minus end of an actin filament [2], while all other myosins move to the plus end [3]. Recently, we proposed that myosin VI moves using three types of steps: large and small forward steps (minus end directed), and backward steps (plus end directed) [4] [5] [6]. "
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    ABSTRACT: Myosin VI is a processive myosin that has a unique stepping motion, which includes three kinds of steps: a large forward step, a small forward step and a backward step. Recently, we proposed the parallel lever arms model to explain the adjacent binding state, which is necessary for the unique motion. In this model, both lever arms are directed the same direction. However, experimental evidence has not refuted the possibility that the adjacent binding state emerges from myosin VI folding its lever arm extension (LAE). To clarify this issue, we constructed a myosin VI/V chimera that replaces the myosin VI LAE with the IQ3-6 domains of the myosin V lever arm, which cannot fold, and performed single molecule imaging. Our chimera showed the same stepping patterns as myosin VI, indicating the LAE is not responsible for the adjacent binding state.
    Preview · Article · Jan 2015 · BIOPHYSICS
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    • "These newly discovered myosin-like molecules are referred to as unconventional myosins. There are about 20 classes of these molecules (Krendel and Mooseker, 2005; Hartman and Spudich, 2012). Redowicz and coworker (Karolczak et al., 2014) review the distribution and roles of one of these unconventional myosins, myosin VIA, in healthy and in diseased striated muscle cells. "

    Full-text · Article · Sep 2014 · The Anatomical Record Advances in Integrative Anatomy and Evolutionary Biology
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