Actin dynamics in the contractile ring during cytokinesis in fission yeast

Pelham, Robert J.; Chang, Fred

doi:10.1038/nature00999

Cited by 314 publications

(355 citation statements)

References 30 publications

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“…S7), because actin tagged with GFP does not incorporate into contractile rings (18,43). CHD, the calponin homology domain from fission yeast IQGAP Rng2p (44), binds to actin filaments with a K d of 20 μM (45), exchanging on and off filaments on a subsecond time scale, much faster than the expected turnover rate of actin (46).…”

Section: Actin Filaments During Formation and Constriction Of Contracmentioning

confidence: 99%

Molecular organization of cytokinesis nodes and contractile rings by super-resolution fluorescence microscopy of live fission yeast

Laplante

Huang

Tebbs

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

123

284

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Cytokinesis in animals, fungi, and amoebas depends on the constriction of a contractile ring built from a common set of conserved proteins. Many fundamental questions remain about how these proteins organize to generate the necessary tension for cytokinesis. Using quantitative high-speed fluorescence photoactivation localization microscopy (FPALM), we probed this question in live fission yeast cells at unprecedented resolution. We show that nodes, protein assembly precursors to the contractile ring, are discrete structural units with stoichiometric ratios and distinct distributions of constituent proteins. Anillin Mid1p, Fes/CIP4 homology-Bin/amphiphysin/ Rvs (F-BAR) Cdc15p, IQ motif containing GTPase-activating protein (IQGAP) Rng2p, and formin Cdc12p form the base of the node that anchors the ends of myosin II tails to the plasma membrane, with myosin II heads extending into the cytoplasm. This general node organization persists in the contractile ring where nodes move bidirectionally during constriction. We observed the dynamics of the actin network during cytokinesis, starting with the extension of short actin strands from nodes, which sometimes connected neighboring nodes. Later in cytokinesis, a broad network of thick bundles coalesced into a tight ring around the equator of the cell. The actin ring was ∼125 nm wide and ∼125 nm thick. These observations establish the organization of the proteins in the functional units of a cytokinetic contractile ring.T he mechanism of cell division by a contractile ring of actin and myosin II appeared in the common ancestor of amoebas, fungi, and animals (1). Although much is known about the protein composition of contractile rings, relatively little is known about the 3D organization of these proteins. This information is required to formulate computer models and simulations to test ideas regarding the mechanisms of contractile ring function.Electron microscopy has shown actin filaments in contractile rings of animal cells (2, 3) and yeast cells (4,5). Myosin II concentrates in cleavage furrow (6) and is the main motor for constricting contractile rings (7,8). In animal cells, electron microscopy has revealed rods the size of myosin II minifilaments in contractile rings (2, 9), and structured-illumination fluorescence microscopy has shown that this myosin II is organized in bipolar assemblies (10). Contractile rings contain other structural and regulatory proteins, including anillin (11), IQ motif containing GTPase-activating proteins (IQGAP) (12), formins (13), alphaactinin (14), and Fes/CIP4 homology-Bin/amphiphysin/Rvs (F-BAR) proteins (15), but how these proteins are anchored to the plasma membrane or organized into functional complexes in animal cells is unknown.Our understanding of the cytokinetic apparatus is most advanced in fission yeast (16). Only in fission yeast do we know the concentrations of the major cytokinesis proteins (17) and the time course of events leading to cellular division (18,19). Molecularly explicit computer models can account for both the ...

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Section: Actin Filaments During Formation and Constriction Of Contracmentioning

confidence: 99%

Molecular organization of cytokinesis nodes and contractile rings by super-resolution fluorescence microscopy of live fission yeast

Laplante

Huang

Tebbs

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

123

284

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“…Branched actin filament arrays, which concentrate at sites of clathrin-mediated endocytosis (2,3) and at the leading edge of motile cells (4), are nucleated by the actin-related protein-2/3 (Arp2/3) complex. In contrast, bundles of unbranched actin filaments, which sometimes mediate vesicle trafficking or form myosin-containing contractile bundles, often are nucleated by formin proteins (5)(6)(7)(8)(9)(10)(11)(12)(13)(14).…”

mentioning

confidence: 99%

Cell-cycle regulation of formin-mediated actin cable assembly

Miao

Wong

Mennella

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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Assembly of appropriately oriented actin cables nucleated by formin proteins is necessary for many biological processes in diverse eukaryotes. However, compared with knowledge of how nucleation of dendritic actin filament arrays by the actin-related protein-2/3 complex is regulated, the in vivo regulatory mechanisms for actin cable formation are less clear. To gain insights into mechanisms for regulating actin cable assembly, we reconstituted the assembly process in vitro by introducing microspheres functionalized with the C terminus of the budding yeast formin Bni1 into extracts prepared from yeast cells at different cell-cycle stages. EM studies showed that unbranched actin filament bundles were reconstituted successfully in the yeast extracts. Only extracts enriched in the mitotic cyclin Clb2 were competent for actin cable assembly, and cyclin-dependent kinase 1 activity was indispensible. Cyclin-dependent kinase 1 activity also was found to regulate cable assembly in vivo. Here we present evidence that formin cellcycle regulation is conserved in vertebrates. The use of the cablereconstitution system to test roles for the key actin-binding proteins tropomyosin, capping protein, and cofilin provided important insights into assembly regulation. Furthermore, using mass spectrometry, we identified components of the actin cables formed in yeast extracts, providing the basis for comprehensive understanding of cable assembly and regulation.Cdk1 | three-dimensional structured-illumination microscopy | actin nucleation E ukaryotic cells contain populations of actin structures with distinct architectures and protein compositions, which mediate varied cellular processes (1). Understanding how F-actin polymerization is regulated in time and space is critical to understanding how actin structures provide mechanical forces for corresponding biological processes. Branched actin filament arrays, which concentrate at sites of clathrin-mediated endocytosis (2, 3) and at the leading edge of motile cells (4), are nucleated by the actin-related protein-2/3 (Arp2/3) complex. In contrast, bundles of unbranched actin filaments, which sometimes mediate vesicle trafficking or form myosin-containing contractile bundles, often are nucleated by formin proteins (5-14).Much has been learned about how branched actin filaments are polymerized by the Arp2/3 complex and how these filaments function in processes such as endocytosis (2, 15). In contrast, relatively little is known about how actin cables are assembled under physiological conditions. In previous studies, branched actin filaments derived from the Arp2/3 complex have been reconstituted using purified proteins (16)(17)(18)(19) or cellular extracts (20-25). When microbeads were coated with nucleation-promoting factors for the Arp2/3 complex and then were incubated in cell extracts, actin comet tails were formed by sequential actin nucleation, symmetry breaking, and tail elongation. Importantly, the motility behavior of F-actin assembled by the Arp2/3 complex using defined, purified pr...

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“…When we performed immunofluorescence staining for Plk1 and Aurora B, proteins known to regulate cytokinesis,11, 12 we found that Plk1 localized at the cytokinesis contractile ring in CLL doublets (Figure 1C), which is a hallmark of cytokinesis 11. Taken together, our results indicate that CLL cell doublets were in the cytokinesis stage of the cell cycle, specifically, after reformation of the nucleus, but before abscission and physical separation of the cytoplasm 11, 13, 14, 15, 16…”

Section: Resultsmentioning

confidence: 52%

“…The described Actin, Tubulin and Plk1 localization corresponds to late steps of cytokinesis, more precisely, to the step after nuclear envelope reformation and chromosome decondensation, but before cytoplasmic abscission by the contractile ring between the 2 daughter cells 11, 13, 14, 15, 16. Previous studies have linked cytokinesis defects, multiple centrosomes and accumulation of cells in G0/1 to be a consequence of dysregulation of important players in cell cycle regulation 34.…”

Section: Discussionmentioning

confidence: 91%

Cytokinesis arrest and multiple centrosomes in B cell chronic lymphocytic leukaemia

Rogne

Svaerd

Madsen‐Østerbye

et al. 2018

J Cellular Molecular Medi

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Cytokinesis failure leads to the emergence of tetraploid cells and multiple centrosomes. Chronic lymphocytic leukaemia (CLL) is the most common haematological malignancy in adults and is characterized by clonal B cell expansion. Here, we show that a significant number of peripheral blood CLL cells are arrested in cytokinesis and that this event occurred after nuclear envelope reformation and before cytoplasmic abscission. mRNA expression data showed that several genes known to be crucial for cell cycle regulation, checkpoint and centromere function, such as ING4, ING5, CDKN1A and CDK4, were significantly dysregulated in CLL samples. Our results demonstrate that CLL cells exhibit difficulties in completing mitosis, which is different from but may, at least in part, explain the previously reported accumulation of CLL cells in G0/1.

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Actin dynamics in the contractile ring during cytokinesis in fission yeast

Cited by 314 publications

References 30 publications

Molecular organization of cytokinesis nodes and contractile rings by super-resolution fluorescence microscopy of live fission yeast

Molecular organization of cytokinesis nodes and contractile rings by super-resolution fluorescence microscopy of live fission yeast

Cell-cycle regulation of formin-mediated actin cable assembly

Cytokinesis arrest and multiple centrosomes in B cell chronic lymphocytic leukaemia

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