Acetylation regulates tropomyosin function in the fission yeast<i>Schizosaccharomyces pombe</i>

Skoumpla, Kalomoira; Coulton, Arthur T.; Lehman, William; Geeves, Michael A.; Mulvihill, Daniel P.

doi:10.1242/jcs.001115

Cited by 80 publications

(136 citation statements)

References 54 publications

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“…In fission yeast acetylation of the tropomyosin, Cdc8, has a significant impact upon the ability of the protein to regulate the interaction between actin and myosin in vitro (Skoumpla et al, 2007). Within S. pombe cells a constant proportion of Cdc8 (~80%) is acetylated, while 20% is unacetylated, however, it has not been possible to determine how each of these subpopulations contribute to the cellular function of this Tm.…”

Section: Resultsmentioning

confidence: 99%

“…Cdc8, the sole Tm of the fission yeast, Schizosaccharomyces pombe, is essential for the formation and maintenance of actin filaments (Balasubramanian et al, 1992;Kurahashi et al, 2002;Pelham and Chang, 2001) and is present in both acetylated and unacetylated forms within the fission yeast cell (Skoumpla et al, 2007). Acetylation increases the affinity of Cdc8 for actin five fold, and dramatically enhances the ability of this conserved coiledcoil protein to regulate myosin activity (Skoumpla et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

“…Acetylation increases the affinity of Cdc8 for actin five fold, and dramatically enhances the ability of this conserved coiledcoil protein to regulate myosin activity (Skoumpla et al, 2007). The significance of the presence of both acetylated and unacetylated forms of Cdc8 within the yeast cell is currently unknown.…”

Section: Introductionmentioning

confidence: 99%

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The recruitment of acetylated and unacetylated tropomyosin to distinct actin polymers permits the discrete regulation of specific myosins in fission yeast

Coulton

East

Galinska-Rakoczy

et al. 2010

Journal of Cell Science

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SummaryTropomyosin (Tm) is a conserved dimeric coiled-coil protein, which forms polymers that curl around actin filaments in order to regulate actomyosin function. Acetylation of the Tm N-terminal methionine strengthens end-to-end bonds, which enhances actin binding as well as the ability of Tm to regulate myosin motor activity in both muscle and non-muscle cells. In this study we explore the function of each Tm form within fission yeast cells. Electron microscopy and live cell imaging revealed that acetylated and unacetylated Tm associate with distinct actin structures within the cell, and that each form has a profound effect upon the shape and integrity of the polymeric actin filament. We show that, whereas Tm acetylation is required to regulate the in vivo motility of class II myosins, acetylated Tm had no effect on the motility of class I and V myosins. These findings illustrate a novel Tm-acetylation-statedependent mechanism for regulating specific actomyosin cytoskeletal interactions.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The recruitment of acetylated and unacetylated tropomyosin to distinct actin polymers permits the discrete regulation of specific myosins in fission yeast

Coulton

East

Galinska-Rakoczy

et al. 2010

Journal of Cell Science

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“…Furthermore, there has been direct in vivo evidence from the fission yeast model system (Johnson et al, 2014). This yeast contains a single Tpm (Cdc8), which exists in either an N-terminally acetylated (80% of total Tpm) or non-acetylated state (Johnson et al, 2014), with the acetylated Tpm associating with actin filaments that are incorporated into the cytokinetic actomyosin ring during mitosis and the unacetylated form associating with more-dynamic actin filaments during interphase (Skoumpla et al, 2007;Coulton et al, 2010). Indeed, forcing the mitotic and interphase formins to switch location, led to a corresponding switch in the acetylated state of Tpms within each actin-Tpm polymer, which -in turn -was shown to redirect the location of the myosin motors in the cell (Johnson et al, 2014).…”

Section: Assembly Of Specific Tpms Into Actin Filamentsmentioning

confidence: 99%

Tropomyosin – master regulator of actin filament function in the cytoskeleton

Gunning

Hardeman

Lappalainen

et al. 2015

Journal of Cell Science

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225

228

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Tropomyosin (Tpm) isoforms are the master regulators of the functions of individual actin filaments in fungi and metazoans. Tpms are coiled-coil parallel dimers that form a head-to-tail polymer along the length of actin filaments. Yeast only has two Tpm isoforms, whereas mammals have over 40. Each cytoskeletal actin filament contains a homopolymer of Tpm homodimers, resulting in a filament of uniform Tpm composition along its length. Evidence for this 'master regulator' role is based on four core sets of observation. First, spatially and functionally distinct actin filaments contain different Tpm isoforms, and recent data suggest that members of the formin family of actin filament nucleators can specify which Tpm isoform is added to the growing actin filament. Second, Tpms regulate wholeorganism physiology in terms of morphogenesis, cell proliferation, vesicle trafficking, biomechanics, glucose metabolism and organ size in an isoform-specific manner. Third, Tpms achieve these functional outputs by regulating the interaction of actin filaments with myosin motors and actin-binding proteins in an isoform-specific manner. Last, the assembly of complex structures, such as stress fibers and podosomes involves the collaboration of multiple types of actin filament specified by their Tpm composition. This allows the cell to specify actin filament function in time and space by simply specifying their Tpm isoform composition.

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“…6A, bottom). In wild type Fim1-mCherry cells, GFP-Cdc8 associates with the contractile ring but not with endocytic actin patches (23,55). However, in the absence of Fim1 (fim1⌬), GFP-Cdc8 localizes to the contractile ring as well as ectopically to endocytic actin patches (23).…”

Section: Fission Yeast Fimbrinmentioning

confidence: 99%

Actin Filament Bundling by Fimbrin Is Important for Endocytosis, Cytokinesis, and Polarization in Fission Yeast

Skau

Courson

Bestul

et al. 2011

Journal of Biological Chemistry

118

117

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Through the coordinated action of diverse actin-binding proteins, cells simultaneously assemble actin filaments with distinct architectures and dynamics to drive different processes. Actin filament cross-linking proteins organize filaments into higher order networks, although the requirement of cross-linking activity in cells has largely been assumed rather than directly tested. Fission yeast Schizosaccharomyces pombe assembles actin into three discrete structures: endocytic actin patches, polarizing actin cables, and the cytokinetic contractile ring. The fission yeast filament cross-linker fimbrin Fim1 primarily localizes to Arp2/3 complex-nucleated branched filaments of the actin patch and by a lesser amount to bundles of linear antiparallel filaments in the contractile ring. It is unclear whether Fim1 associates with bundles of parallel filaments in actin cables. We previously discovered that a principal role of Fim1 is to control localization of tropomyosin Cdc8, thereby facilitating cofilinmediated filament turnover. Therefore, we hypothesized that the bundling ability of Fim1 is dispensable for actin patches but is important for the contractile ring and possibly actin cables. By directly visualizing actin filament assembly using total internal reflection fluorescence microscopy, we determined that Fim1 bundles filaments in both parallel and antiparallel orientations and efficiently bundles Arp2/3 complex-branched filaments in the absence but not the presence of actin capping protein. Examination of cells exclusively expressing a truncated version of Fim1 that can bind but not bundle actin filaments revealed that bundling activity of Fim1 is in fact important for all three actin structures. Therefore, fimbrin Fim1 has diverse roles as both a filament "gatekeeper" and as a filament cross-linker.

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Acetylation regulates tropomyosin function in the fission yeastSchizosaccharomyces pombe

Cited by 80 publications

References 54 publications

The recruitment of acetylated and unacetylated tropomyosin to distinct actin polymers permits the discrete regulation of specific myosins in fission yeast

The recruitment of acetylated and unacetylated tropomyosin to distinct actin polymers permits the discrete regulation of specific myosins in fission yeast

Tropomyosin – master regulator of actin filament function in the cytoskeleton

Actin Filament Bundling by Fimbrin Is Important for Endocytosis, Cytokinesis, and Polarization in Fission Yeast

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