Our goals are to understand the mechanisms of cytokinesis and of motility contributed by myosin-I. To reach these goals, we propose to use biochemistry, genetics and microscopy, largely with the fission yeast, Schizosaccharomyces pombe, as our experimental organism. Project 1. Regulation of cytokinesis. We will determine genetic interactions between the two isoforms of fission yeast myosin-Il and other gene products known to participate in cytokinesis. We will use genetic screens to identify new components that regulate the time and position of furrow formation, with the long term goal of tracing the signaling pathway from the mitotic spindle to the cleavage furrow, where the contractile ring of actin filaments and myosin-Il divides the two daughter cells. To understand the mechanisms and functions of the products of these genes, we will purify and characterize the isoforms of myosin-Il and accessory proteins that participate in cytokinesis. We will test hypotheses arising from our biochemical studies and genetic analysis at the cellular level using live cell imaging and photobleaching to study the dynamics of the proteins. To understand the assembly of myosin-Il in more detail, we will complete our work on the crystal structure of the C-terminal assembly domain of the tail of Acanthamoeba myosin-Il. Project 2. Structure and functions of myosin-I in fission yeast. Our previous studies implicated the product of the single S. pombe myosin-I gene in the organization of actin filament networks, so we will study the biochemical interactions of the various domains of myosin-I with the WASp homologue (Wsp1p), verprolin (Vrp1p) and Arp2/3 complex to learn how these proteins control actin filament assembly. We will also seek new genetic interactions of these components with other components of the actin system and study the dynamics of these proteins in live cells. The combination of genetics, biochemistry and microscopy of fission yeast offers great advantages for establishing the molecular pathways controlling actin assembly.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
2R01GM026132-26
Application #
6544627
Study Section
Special Emphasis Panel (ZRG1-CDF-4 (02))
Program Officer
Deatherage, James F
Project Start
1978-07-01
Project End
2006-06-30
Budget Start
2002-07-01
Budget End
2003-06-30
Support Year
26
Fiscal Year
2002
Total Cost
$408,750
Indirect Cost
Name
Yale University
Department
Physiology
Type
Schools of Arts and Sciences
DUNS #
082359691
City
New Haven
State
CT
Country
United States
Zip Code
06520
Arasada, Rajesh; Sayyad, Wasim A; Berro, Julien et al. (2018) High-speed superresolution imaging of the proteins in fission yeast clathrin-mediated endocytic actin patches. Mol Biol Cell 29:295-303
Friend, Janice E; Sayyad, Wasim A; Arasada, Rajesh et al. (2018) Fission yeast Myo2: Molecular organization and diffusion in the cytoplasm. Cytoskeleton (Hoboken) 75:164-173
Dey, Sumit K; Pollard, Thomas D (2018) Involvement of the septation initiation network in events during cytokinesis in fission yeast. J Cell Sci 131:
Akamatsu, Matthew; Lin, Yu; Bewersdorf, Joerg et al. (2017) Analysis of interphase node proteins in fission yeast by quantitative and superresolution fluorescence microscopy. Mol Biol Cell 28:3203-3214
Pollard, Thomas D (2017) Nine unanswered questions about cytokinesis. J Cell Biol 216:3007-3016
Pollard, Thomas D (2017) What We Know and Do Not Know About Actin. Handb Exp Pharmacol 235:331-347
Laplante, Caroline; Pollard, Thomas D (2017) Response to Zambon et al. Curr Biol 27:R101-R102
Courtemanche, Naomi; Pollard, Thomas D; Chen, Qian (2016) Avoiding artefacts when counting polymerized actin in live cells with LifeAct fused to fluorescent proteins. Nat Cell Biol 18:676-83
Laplante, Caroline; Huang, Fang; Tebbs, Irene R et al. (2016) Molecular organization of cytokinesis nodes and contractile rings by super-resolution fluorescence microscopy of live fission yeast. Proc Natl Acad Sci U S A 113:E5876-E5885
Pollard, Thomas D (2016) Actin and Actin-Binding Proteins. Cold Spring Harb Perspect Biol 8:

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