An actin point‐mutation neighboring the ‘hydrophobic plug’ causes defects in the maintenance of cell polaroty and septum organization in the fission yeast <i>Schizosaccharomyces pombe</i>

Ishiguro, Junpei; Kobayashi, Wataru

doi:10.1016/0014-5793(96)00819-8

Cited by 55 publications

(59 citation statements)

References 34 publications

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“…To examine the delay in anaphase A onset more accurately, we monitored centromere dynamics in the actin mutant cps8-188 and in cdc11-123 cells, in which astral microtubule attachment to the spindle pole and spindle rotation are compromised (Ishiguro and Kobayashi, 1996;Krapp et al, 2001;Gachet et al, 2004). Single cell analysis revealed that cps8-118 ndc80-gfp cells remained in prometaphase and metaphase for 20 Ϯ 3 min ( Figure 7A), longer than in wild-type cells at the same temperature, but similar to that observed in wildtype cells in the presence of 1.25 M latrunculin A (Figure 2), consistent with our previous observations (Gachet et al, 2004).…”

Section: The Soc Is Activated By Disruption Of Astral Microtubule Conmentioning

confidence: 99%

Disruption of Astral Microtubule Contact with the Cell Cortex Activates a Bub1, Bub3, and Mad3-dependent Checkpoint in Fission Yeast

Tournier¹,

Gachet

Buck³

et al. 2004

MBoC

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In animal and yeast cells, the mitotic spindle is aligned perpendicularly to the axis of cell division. This ensures that sister chromatids are separated to opposite sides of the cytokinetic actomyosin ring. In fission yeast, spindle rotation is dependent upon the interaction of astral microtubules with the cortical actin cytoskeleton. In this article, we show that addition of Latrunculin A, which prevents spindle rotation, delays the separation of sister chromatids and anaphase promoting complex-mediated destruction of spindle-associated Securin and Cyclin B. Moreover, we find that whereas sister kinetochore pairs normally congress to the spindle midzone before anaphase onset, this congression is disrupted when astral microtubule contact with the actin cytoskeleton is disturbed. By analyzing the timing of kinetochore separation, we find that this anaphase delay requires the Bub3, Mad3, and Bub1 but not the Mad1 or Mad2 spindle assembly checkpoint proteins. In agreement with this, we find that Bub1 remains associated with kinetochores when spindles are mispositioned. These data indicate that, in fission yeast, astral microtubule contact with the medial cell cortex is monitored by a subset of spindle assembly checkpoint proteins. We propose that this checkpoint ensures spindles are properly oriented before anaphase takes place. INTRODUCTIONIn eukaryotes, the separation of sister chromatids is mediated by the interaction of spindle microtubules with specialized regions of chromosomes known as kinetochores. At the start of prometaphase, kinetochores are not attached to microtubules. The kinetochore of one sister chromatid then captures a microtubule nucleated from a spindle pole. Once its sister kinetochore has captured microtubules from the other pole, the chromosome becomes bioriented. During metaphase, all bioriented chromosomes move to the equatorial plane, known in animal cells as the metaphase plate, in a process called chromosome congression (Rieder and Salmon, 1994). At anaphase, cohesion is lost, allowing sister chromatids to separate to their respective poles. Finally, the cytokinetic actomyosin ring contracts perpendicularly to, and at the site of, the spindle midzone to ensure that each set of sister chromatids is separated to daughter cells.Cell cycle progression in all eukaryotic cells is monitored by a series of checkpoints that ensure both the fidelity and the temporal and spatial order of cell cycle events (Hartwell and Weinert, 1989). One of the best studied of these is a checkpoint that monitors the assembly of the mitotic spindle (Yu, 2002;Zhou et al., 2002;Cleveland et al., 2003). Components of this checkpoint, which is often referred to as the spindle assembly checkpoint (SAC), were first identified in budding yeast and include the Mad1, Mad2, Mad3, Bub1, Bub3, and Mps1 proteins (Li and Murray, 1991;Hoyt et al., 1991;Weiss and Winey, 1996). Structural and functional homologues of these proteins have been identified in all other eukaryotes so far examined, including fission yeast (He et al., 19...

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Section: The Soc Is Activated By Disruption Of Astral Microtubule Conmentioning

confidence: 99%

Disruption of Astral Microtubule Contact with the Cell Cortex Activates a Bub1, Bub3, and Mad3-dependent Checkpoint in Fission Yeast

Tournier¹,

Gachet

Buck³

et al. 2004

MBoC

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“…The ring is made of actin, one or possibly two myosins (Myo2p and Myp2), a tropomyosin (Cdc8p), and presumably two light chains, one of which is Cdc4p (5,9,12,13,23,28,32). Although intact myosin has yet to be purified from S. pombe, there is genetic, biochemical, and structural evidence in favor of a role for Cdc4p as a myosin essential light chain (9,11).…”

Section: Is the Sole Function Of Cdc4p That Of A Myosin Essentialmentioning

confidence: 99%

Cdc4p, a Contractile Ring Protein Essential for Cytokinesis inSchizosaccharomyces pombe, Interacts with a Phosphatidylinositol 4-Kinase

Desautels

Haese

Slupsky

et al. 2001

Journal of Biological Chemistry

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The proposed function of Cdc4p, an essential contractile ring protein in Schizosaccharomyces pombe, is that of a myosin essential light chain. However, five conditionally lethal cdc4 alleles exhibit complementation in diploids. Such interallelic complementation is not readily explained if the sole function of Cdc4p is that of a myosin essential light chain. Complementation of cdc4 alleles could occur only if different mutant forms can assemble into an active oligomeric complex or if Cdc4p has more than one essential function. To search for other proteins that may interact with Cdc4p, we performed a two-hybrid screen and identified two such candidates: one similar to Saccharomyces cerevisiae Vps27p and the other a putative phosphatidylinositol (PI) 4-kinase. Binding of Cdc4p to the latter and to myosin heavy chain (Myo2p) was confirmed by immunosorbent assays. Deletion studies demonstrated interaction between the Cdc4p C-terminal domain and the PI 4-kinase C-terminal domain. Furthermore, interaction was abolished by the Cdc4p C-terminal domain point mutation, Gly 107 to Ser. This allele also causes failure of cytokinesis. Ectopic expression of the PI 4-kinase C-terminal domain caused cytokinesis defects that were most extreme in cells carrying the G107S allele. We suggest that Cdc4p plays multiple roles in cytokinesis and that interaction with a PI 4-kinase may be important for contractile ring assembly and/or function.

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“…The F-actin patches localize to both growing ends of the cylindrical cell during interphase. It is suggested that the F-actin patches play a role in polarized cell growth (Kobori et al, 1989;Ishiguro and Kobayashi, 1996). The localization of F-actin patches has been shown to be controlled by small GTPbinding proteins and various actin-modulating proteins (for review see Gould and Simanis, 1997;Ishiguro, 1998;Le Goff et al, 1999).…”

Section: Assembly Of the Contractile Ring Introductionmentioning

confidence: 99%

Advances in Cytokinesis Research. Contractile Ring Formation in Xenopus Egg and Fission Yeast.

Noguchi

Arai

Motegi

et al. 2001

Cell Struct. Funct.

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ABSTRACT. How actin filaments (F-actin) and myosin II (myosin) assemble to form the contractile ring was investigated with fission yeast and Xenopus egg. In fission yeast cells, an aster-like structure composed of F-actin cables is formed at the medial cortex of the cell during prophase to metaphase, and a single F-actin cable(s) extends from this structure, which seems to be a structural basis of the contractile ring. In early mitosis, myosin localizes as dots in the medial cortex independently of F-actin. Then they fuse with each other and are packed into a thin contractile ring.At the growing ends of the cleavage furrow of Xenopus eggs, F-actin at first assembles to form patches. Next they fuse with each other to form short F-actin bundles. The short bundles then form long bundles. Myosin seems to be transported by the cortical movement to the growing end and assembles there as spots earlier than F-actin. Actin polymerization into the patches is likely to occur after accumulation of myosin. The myosin spots and the F-actin patches are simultaneously reorganized to form the contractile ring bundles.The idea that a Ca signal triggers cleavage furrow formation was tested with Xenopus eggs during the first cleavage. We could not detect any Ca signals such as a Ca wave, Ca puffs or even Ca blips at the growing end of the cleavage furrow. Furthermore, cleavages are not affected by Ca-chelators injected into the eggs at concentrations sufficient to suppress the Ca waves. Thus we conclude that formation of the contractile ring is not induced by a Ca signal at the growing end of the cleavage furrow.

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An actin point‐mutation neighboring the ‘hydrophobic plug’ causes defects in the maintenance of cell polaroty and septum organization in the fission yeast Schizosaccharomyces pombe

Cited by 55 publications

References 34 publications

Disruption of Astral Microtubule Contact with the Cell Cortex Activates a Bub1, Bub3, and Mad3-dependent Checkpoint in Fission Yeast

Disruption of Astral Microtubule Contact with the Cell Cortex Activates a Bub1, Bub3, and Mad3-dependent Checkpoint in Fission Yeast

Cdc4p, a Contractile Ring Protein Essential for Cytokinesis inSchizosaccharomyces pombe, Interacts with a Phosphatidylinositol 4-Kinase

Advances in Cytokinesis Research. Contractile Ring Formation in Xenopus Egg and Fission Yeast.

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