scholarly journals The Mammalian Septin MSF Localizes with Microtubules and Is Required for Completion of Cytokinesis

2002 ◽  
Vol 13 (10) ◽  
pp. 3532-3545 ◽  
Author(s):  
Mark C. Surka ◽  
Christopher W. Tsang ◽  
William S. Trimble
Keyword(s):  
Cell Death ◽  
Cell Division ◽  
Nuclear Division ◽  
Cleavage Furrow ◽  
Small Interfering Rnas ◽  
Animal Cells ◽  
Central Spindle ◽  
Synchronized Cells ◽  
Binucleated Cells ◽  
And Function

Cytokinesis in animal cells involves the contraction of an actomyosin ring formed at the cleavage furrow. Nuclear division, or karyokinesis, must be precisely timed to occur before cytokinesis in order to prevent genetic anomalies that would result in either cell death or uncontrolled cell division. The septin family of GTPase proteins has been shown to be important for cytokinesis although little is known about their role during this process. Here we investigate the distribution and function of the mammalian septin MSF. We show that during interphase, MSF colocalizes with actin, microtubules, and another mammalian septin, Nedd5, and coprecipitates with six septin proteins. In addition, transfections of various MSF isoforms reveal that MSF-A specifically localizes with microtubules and that this localization is disrupted by nocodazole treatment. Furthermore, MSF isoforms localize primarily with tubulin at the central spindle during mitosis, whereas Nedd5 is mainly associated with actin. Microinjection of affinity-purified anti-MSF antibodies into synchronized cells, or depletion of MSF by small interfering RNAs, results in the accumulation of binucleated cells and in cells that have arrested during cytokinesis. These results reveal that MSF is required for the completion of cytokinesis and suggest a role that is distinct from that of Nedd5.

Nocodazole and cytochalasin D induce tetraploidy in mammalian cells

1984 ◽  
Vol 246 (1) ◽  
pp. C154-C156 ◽  
Author(s):  
G. W. Zieve
Keyword(s):  
Cell Division ◽  
Mammalian Cells ◽  
Cytochalasin D ◽  
Microtubule Assembly ◽  
Reversible Inhibitor ◽  
Cleavage Furrow ◽  
Synchronized Cells ◽  
Cells In Culture ◽  
Wide Range

Nocodazole, a rapidly reversible inhibitor of microtubule assembly is useful for preparing mammalian cells synchronized at all stages of mitosis. When synchronized cells are allowed to progress through mitosis in the presence of cytochalasin D, the cleavage furrow is inhibited and dikaryon cells are formed. These cells become homogeneous populations of stable mononuclear tetraploid cells after the following cell division. This procedure is applicable to a wide range of mammalian cells in culture.

scholarly journals ppGpp functions as an alarmone in metazoa

2019 ◽  
Author(s):  
Doshun Ito ◽  
Hinata Kawamura ◽  
Akira Oikawa ◽  
Yuta Ihara ◽  
Toshio Shibata ◽  
...  
Keyword(s):  
Cell Death ◽  
Drosophila Melanogaster ◽  
Environmental Changes ◽  
Nutrient Deficiency ◽  
Stringent Response ◽  
Human Cells ◽  
Metabolic Changes ◽  
Animal Cells ◽  
Physiological Relevance ◽  
And Function

AbstractGuanosine 3’,5’-bis(pyrophosphate) (ppGpp) functions as a second messenger in bacteria to adjust their physiology in response to environmental changes. In recent years, the ppGpp-specific hydrolase, metazoan SpoT homolog-1 (Mesh1), was shown to have important roles for growth under nutrient deficiency in Drosophila melanogaster. Curiously, however, ppGpp has never been detected in animal cells, and therefore the physiological relevance of this molecule, if any, in metazoans has not been established. Here, we report the detection of ppGpp in Drosophila and human cells and demonstrate that ppGpp accumulation induces metabolic changes, cell death, and eventually lethality in Drosophila. Our results provide the first evidence of the existence and function of the ppGpp-dependent stringent response in animals.

scholarly journals KIF14 and citron kinase act together to promote efficient cytokinesis

2006 ◽  
Vol 172 (3) ◽  
pp. 363-372 ◽  
Author(s):  
Ulrike Gruneberg ◽  
Rüdiger Neef ◽  
Xiuling Li ◽  
Eunice H.Y. Chan ◽  
Ravindra B. Chalamalasetty ◽  
...  
Keyword(s):  
Cell Division ◽  
Human Cell ◽  
Cleavage Furrow ◽  
General Requirement ◽  
Central Spindle ◽  
Microtubule Associated Proteins ◽  
Cell Biol ◽  
Associated Proteins ◽  
Essential Function ◽  
Citron Kinase

Multiple mitotic kinesins and microtubule-associated proteins (MAPs) act in concert to direct cytokinesis (Glotzer, M. 2005. Science. 307:1735–1739). In anaphase cells, many of these proteins associate with an antiparallel array of microtubules termed the central spindle. The MAP and microtubule-bundling protein PRC1 (protein-regulating cytokinesis 1) is one of the key molecules required for the integrity of this structure (Jiang, W., G. Jimenez, N.J. Wells, T.J. Hope, G.M. Wahl, T. Hunter, and R. Fukunaga. 1998. Mol. Cell. 2:877–885; Mollinari, C., J.P. Kleman, W. Jiang, G. Schoehn, T. Hunter, and R.L. Margolis. 2002. J. Cell Biol. 157:1175–1186). In this study, we identify an interaction between endogenous PRC1 and the previously uncharacterized kinesin KIF14 as well as other mitotic kinesins (MKlp1/CHO1, MKlp2, and KIF4) with known functions in cytokinesis (Hill, E., M. Clarke, and F.A. Barr. 2000. EMBO J. 19:5711–5719; Matuliene, J., and R. Kuriyama. 2002. Mol. Biol. Cell. 13:1832–1845; Kurasawa, Y., W.C. Earnshaw, Y. Mochizuki, N. Dohmae, and K. Todokoro. 2004. EMBO J. 23:3237–3248). We find that KIF14 targets to the central spindle via its interaction with PRC1 and has an essential function in cytokinesis. In KIF14-depleted cells, citron kinase but not other components of the central spindle and cleavage furrow fail to localize. Furthermore, the localization of KIF14 and citron kinase to the central spindle and midbody is codependent, and they form a complex depending on the activation state of citron kinase. Contrary to a previous study (Di Cunto, F., S. Imarisio, E. Hirsch, V. Broccoli, A. Bulfone, A. Migheli, C. Atzori, E. Turco, R. Triolo, G.P. Dotto, et al. 2000. Neuron. 28:115–127), we find a general requirement for citron kinase in human cell division. Together, these findings identify a novel pathway required for efficient cytokinesis.

scholarly journals ppGpp functions as an alarmone in metazoa

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Doshun Ito ◽  
Hinata Kawamura ◽  
Akira Oikawa ◽  
Yuta Ihara ◽  
Toshio Shibata ◽  
...  
Keyword(s):  
Cell Death ◽  
Drosophila Melanogaster ◽  
Environmental Changes ◽  
Nutrient Deficiency ◽  
Stringent Response ◽  
Human Cells ◽  
Metabolic Changes ◽  
Animal Cells ◽  
Physiological Relevance ◽  
And Function

AbstractGuanosine 3′,5′-bis(pyrophosphate) (ppGpp) functions as a second messenger in bacteria to adjust their physiology in response to environmental changes. In recent years, the ppGpp-specific hydrolase, metazoan SpoT homolog-1 (Mesh1), was shown to have important roles for growth under nutrient deficiency in Drosophila melanogaster. Curiously, however, ppGpp has never been detected in animal cells, and therefore the physiological relevance of this molecule, if any, in metazoans has not been established. Here, we report the detection of ppGpp in Drosophila and human cells and demonstrate that ppGpp accumulation induces metabolic changes, cell death, and eventually lethality in Drosophila. Our results provide the evidence of the existence and function of the ppGpp-dependent stringent response in animals.

scholarly journals An astral simulacrum of the central spindle accounts for normal, spindle-less, and anucleate cytokinesis in echinoderm embryos

2014 ◽  
Vol 25 (25) ◽  
pp. 4049-4062 ◽  
Author(s):  
Kuan-Chung Su ◽  
William M. Bement ◽  
Mark Petronczki ◽  
George von Dassow
Keyword(s):  
Animal Cells ◽  
Spatial Cues ◽  
Multiple Signals ◽  
Central Spindle ◽  
Binding Partner ◽  
Spindle Midzone ◽  
And Function ◽  
Equatorial Band

Cytokinesis in animal cells depends on spindle-derived spatial cues that culminate in Rho activation, and thereby actomyosin assembly, in a narrow equatorial band. Although the nature, origin, and variety of such cues have long been obscure, one component is certainly the Rho activator Ect2. Here we describe the behavior and function of Ect2 in echinoderm embryos, showing that Ect2 migrates from spindle midzone to astral microtubules in anaphase and that Ect2 shapes the pattern of Rho activation in incipient furrows. Our key finding is that Ect2 and its binding partner Cyk4 accumulate not only at normal furrows, but also at furrows that form in the absence of associated spindle, midzone, or chromosomes. In all these cases, the cell assembles essentially the same cytokinetic signaling ensemble—opposed astral microtubules decorated with Ect2 and Cyk4. We conclude that if multiple signals contribute to furrow induction in echinoderm embryos, they likely converge on the same signaling ensemble on an analogous cytoskeletal scaffold.

Control of cortical contractility during cytokinesis

2008 ◽  
Vol 36 (3) ◽  
pp. 371-377 ◽  
Author(s):  
Michael Werner ◽  
Michael Glotzer
Keyword(s):  
Molecular Mechanisms ◽  
Current Understanding ◽  
Cleavage Furrow ◽  
Wild Type ◽  
Animal Cells ◽  
Central Spindle ◽  
Local Increase ◽  
Cortical Contractility ◽  
Differential Control

Cleavage furrow formation in animal cells results from a local increase in cortical contractility. During anaphase, the spindle contains, in addition to astral arrays of microtubules, a set of bundled microtubules known as the central spindle. Each of these populations of microtubules, the astral arrays and the central spindle bundles, is sufficient to direct cleavage furrow formation, yet in wild-type situations these sets of microtubules co-operate to induce furrow formation at the same site, between the segregating chromosomes. These pathways have distinct genetic requirements that reflect their differential control of cortical actomyosin. We review our current understanding of the molecular mechanisms of furrow formation, with particular emphasis on the central spindle-independent pathway.

scholarly journals Microtubule plus-tips act as signaling hubs for positioning the cleavage furrow during cytokinesis

2018 ◽  
Author(s):  
Vikash Verma ◽  
Thomas J. Maresca
Keyword(s):  
Drosophila Melanogaster ◽  
Cell Division ◽  
Aurora B ◽  
Cleavage Furrow ◽  
Myosin Regulatory Light Chain ◽  
Animal Cells ◽  
Contractile Ring ◽  
Rhoa Activation ◽  
Polo Kinase ◽  
Molecular Nature

ABSTRACTCell division in animal cells culminates with the formation of a contractile ring that divides the cytosol through formation of a cleavage furrow. Microtubules (MTs) are essential for furrow positioning, but the molecular nature of MT-derived spatial signals is unresolved. In this study essential cytokinesis regulators (the centralspindlin complex, aurora B kinase (ABK), and polo kinase) were visualized in Drosophila melanogaster (Dm) cells and found localize to and track MT plus-ends during cytokinesis. The RhoA GEF Pebble (Dm ECT2) did not robustly tip-track but became enriched at MT plus-tips rapidly following cortical contact resulting in RhoA activation and enrichment of myosin-regulatory light chain. Abrogation of cytokinesis regulator tip-tracking by EB1 depletion or deletion of a novel EB1-interaction motif (hxxPTxh) in the centralspindlin component RacGAP50C resulted in higher incidences of cytokinesis failure. We propose that EB1-dependent, MT plus-tip-based signaling hubs recruit cortical Dm ECT2 upon contact to locally activate RhoA.

scholarly journals Cell Elongation and Cell Death ofHelicobacter pyloriIs Modulated by the Disruption ofcdrA(Cell Division-Related Gene A)

2006 ◽  
Vol 50 (7) ◽  
pp. 487-497 ◽  
Author(s):  
Hiroaki Takeuchi ◽  
Teruko Nakazawa ◽  
Takeshi Okamoto ◽  
Mutsunori Shirai ◽  
Mitsuo Kimoto ◽  
...  
Keyword(s):  
Cell Death ◽  
Cell Division ◽  
Cell Elongation ◽  
Related Gene

Meiosis in Coprinus Lagopus: A Comparative Study with Light and Electron Microscopy

1967 ◽  
Vol 2 (4) ◽  
pp. 529-536
Author(s):  
B. C. LU
Keyword(s):  
Nuclear Fusion ◽  
Light And Electron Microscopy ◽  
Central Component ◽  
Fruiting Bodies ◽  
Homologous Pairing ◽  
Animal Cells ◽  
Characteristic Structure ◽  
Homologous Chromosomes ◽  
Central Spindle ◽  
Spindle Microtubules

Meiosis within fruiting bodies of Coprinus lagopus Fr. is closely synchronized. This conveniently facilitates joint light- and electron-microscope observations. Before nuclear fusion the chromatin appears diffuse in the light microscope; after nuclear fusion individual chromosomes can be recognized. In the electron micrographs the chromatin of pre-fusion and early fusion nuclei cannot be recognized as defined structures with the fixation and staining procedures employed. At the time of synapsis the lateral components of the synaptinemal complexes can be seen in the micrographs. The pairing process of the two chromosomes of the homologous pairs is believed to involve two steps: (1) two homologous chromosomes become aligned in parallel, and (2) pairing occurs by formation of the synaptinemal complex including the central synaptic component. The term synaptic centre is coined for the central component, which is believed to be the zone where crossing-over occurs. The formation of this structure in relation to homologous pairing, and the structural organization of the synaptinemal complexes are discussed. At meiotic metaphase, the chromosomes congregate around the central spindle microtubules. They are contracted and contain densely packed chromatin fibrils. Two types of spindle microtubules are demonstrated: (1) the chromosomal microtubules directly connecting the chromosomes to the centrosomes, and (2) the central spindle microtubules connecting the two centrosomes. The centrosomes are round, fibril-containing bodies approximately 0.3 µ in diameter. They have been observed outside the nuclear envelope at pachytene, but do not show the characteristic structure normally found in animal cells.

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