scholarly journals Dialogue between centrosomal entrance and exit scaffold pathways regulates mitotic commitment

2017 ◽  
Vol 216 (9) ◽  
pp. 2795-2812 ◽  
Author(s):  
Kuan Yoow Chan ◽  
Marisa Alonso-Nuñez ◽  
Agnes Grallert ◽  
Kayoko Tanaka ◽  
Yvonne Connolly ◽  
...  
Keyword(s):  
Fission Yeast ◽  
Cell Fate ◽  
Control Cell ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Casein Kinase ◽  
Mitotic Exit ◽  
Cyclin B ◽  
Pole Body ◽  
Scaffold Molecule

The fission yeast scaffold molecule Sid4 anchors the septum initiation network to the spindle pole body (SPB, centrosome equivalent) to control mitotic exit events. A second SPB-associated scaffold, Cut12, promotes SPB-associated Cdk1–cyclin B to drive mitotic commitment. Signals emanating from each scaffold have been assumed to operate independently to promote two distinct outcomes. We now find that signals from Sid4 contribute to the Cut12 mitotic commitment switch. Specifically, phosphorylation of Sid4 by NIMAFin1 reduces Sid4 affinity for its SPB anchor, Ppc89, while also enhancing Sid4’s affinity for casein kinase 1δ (CK1δ). The resulting phosphorylation of Sid4 by the newly docked CK1δ recruits Chk2Cds1 to Sid4. Chk2Cds1 then expels the Cdk1–cyclin B antagonistic phosphatase Flp1/Clp1 from the SPB. Flp1/Clp1 departure can then support mitotic commitment when Cdk1–cyclin B activation at the SPB is compromised by reduction of Cut12 function. Such integration of signals emanating from neighboring scaffolds shows how centrosomes/SPBs can integrate inputs from multiple pathways to control cell fate.

Distinct nuclear and spindle pole body populations of cyclin–cdc2 in fission yeast

Nature ◽  
1990 ◽  
Vol 347 (6294) ◽  
pp. 680-682 ◽  
Author(s):  
Caroline E. Alfa ◽  
Bernard Ducommun ◽  
David Beach ◽  
Jeremy S. Hyams
Keyword(s):  
Fission Yeast ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Pole Body

scholarly journals The Fission Yeast Homolog of the Human Transcription Factor EAP30 Blocks Meiotic Spindle Pole Body Amplification

2005 ◽  
Vol 9 (1) ◽  
pp. 63-73 ◽  
Author(s):  
Ye Jin ◽  
Joel J. Mancuso ◽  
Satoru Uzawa ◽  
Daniela Cronembold ◽  
W. Zacheus Cande
Keyword(s):  
Transcription Factor ◽  
Fission Yeast ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Meiotic Spindle ◽  
Pole Body ◽  
Yeast Homolog ◽  
Human Transcription Factor

scholarly journals A microtubule polymerase cooperates with the kinesin-6 motor and a microtubule cross-linker to promote bipolar spindle assembly in the absence of kinesin-5 and kinesin-14 in fission yeast

2017 ◽  
Vol 28 (25) ◽  
pp. 3647-3659 ◽  
Author(s):  
Masashi Yukawa ◽  
Tomoki Kawakami ◽  
Masaki Okazaki ◽  
Kazunori Kume ◽  
Ngang Heok Tang ◽  
...  
Keyword(s):  
Fission Yeast ◽  
Chromosome Segregation ◽  
Spindle Pole Body ◽  
Spindle Assembly ◽  
Spindle Pole ◽  
Temperature Sensitive ◽  
Bipolar Spindle ◽  
Pole Body ◽  
Cross Linker ◽  
Spindle Elongation

Accurate chromosome segregation relies on the bipolar mitotic spindle. In many eukaryotes, spindle formation is driven by the plus-end–directed motor kinesin-5 that generates outward force to establish spindle bipolarity. Its inhibition leads to the emergence of monopolar spindles with mitotic arrest. Intriguingly, simultaneous inactivation of the minus-end–directed motor kinesin-14 restores spindle bipolarity in many systems. Here we show that in fission yeast, three independent pathways contribute to spindle bipolarity in the absence of kinesin-5/Cut7 and kinesin-14/Pkl1. One is kinesin-6/Klp9 that engages with spindle elongation once short bipolar spindles assemble. Klp9 also ensures the medial positioning of anaphase spindles to prevent unequal chromosome segregation. Another is the Alp7/TACC-Alp14/TOG microtubule polymerase complex. Temperature-sensitive alp7cut7pkl1 mutants are arrested with either monopolar or very short spindles. Forced targeting of Alp14 to the spindle pole body is sufficient to render alp7cut7pkl1 triply deleted cells viable and promote spindle assembly, indicating that Alp14-mediated microtubule polymerization from the nuclear face of the spindle pole body could generate outward force in place of Cut7 during early mitosis. The third pathway involves the Ase1/PRC1 microtubule cross-linker that stabilizes antiparallel microtubules. Our study, therefore, unveils multifaceted interplay among kinesin-dependent and -independent pathways leading to mitotic bipolar spindle assembly.

Two-hybrid search for proteins that interact with Sad1 and Kms1, two membrane-bound components of the spindle pole body in fission yeast

2003 ◽  
Vol 270 (6) ◽  
pp. 449-461 ◽  
Author(s):  
F. Miki ◽  
A. Kurabayashi ◽  
Y. Tange ◽  
K. Okazaki ◽  
M. Shimanuki ◽  
...  
Keyword(s):  
Fission Yeast ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Hybrid Search ◽  
Pole Body ◽  
Membrane Bound ◽  
Two Hybrid

scholarly journals Cut1/separase C-terminus affects spindle pole body positioning in interphase of fission yeast: pointed nuclear formation

2002 ◽  
Vol 7 (11) ◽  
pp. 1113-1124 ◽  
Author(s):  
Takahiro Nakamura ◽  
Koji Nagao ◽  
Yukinobu Nakaseko ◽  
Mitsuhiro Yanagida
Keyword(s):  
Fission Yeast ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Pole Body ◽  
C Terminus ◽  
Body Positioning

scholarly journals Spindle Pole Body Duplication in Fission Yeast Occurs at the G1/S Boundary but Maturation Is Blocked until Exit from S by an Event Downstream of Cdc10+

2004 ◽  
Vol 15 (12) ◽  
pp. 5219-5230 ◽  
Author(s):  
Satoru Uzawa ◽  
Fei Li ◽  
Ye Jin ◽  
Kent L. McDonald ◽  
Michael B. Braunfeld ◽  
...  
Keyword(s):  
Fission Yeast ◽  
Spindle Pole Body ◽  
Specific Inhibitor ◽  
Spindle Pole ◽  
Feedback Mechanism ◽  
G1 Arrest ◽  
Restrictive Temperature ◽  
Permissive Temperature ◽  
Pole Body ◽  
In Cells

The regulation and timing of spindle pole body (SPB) duplication and maturation in fission yeast was examined by transmission electron microscopy. When cells are arrested at G1 by nitrogen starvation, the SPB is unduplicated. On release from G1, the SPBs were duplicated after 1–2 h. In cells arrested at S by hydroxyurea, SPBs are duplicated but not mature. In G1 arrest/release experiments with cdc2.33 cells at the restrictive temperature, SPBs remained single, whereas in cells at the permissive temperature, SPBs were duplicated. In cdc10 mutant cells, the SPBs seem not only to be duplicated but also to undergo partial maturation, including invagination of the nuclear envelope underneath the SPB. There may be an S-phase–specific inhibitor of SPB maturation whose expression is under control of cdc10+. This model was examined by induction of overreplication of the genome by overexpression of rum1p or cdc18p. In cdc18p-overexpressing cells, the SPBs are duplicated but not mature, suggesting that cdc18p is one component of this feedback mechanism. In contrast, cells overexpressing rum1p have large, deformed SPBs accompanied by other features of maturation and duplication. We propose a feedback mechanism for maturation of the SPB that is coupled with exit from S to trigger morphological changes.

scholarly journals The cortical protein Lte1 promotes mitotic exit by inhibiting the spindle position checkpoint kinase Kin4

2011 ◽  
Vol 193 (6) ◽  
pp. 1033-1048 ◽  
Author(s):  
Daniela Trinca Bertazzi ◽  
Bahtiyar Kurtulmus ◽  
Gislene Pereira
Keyword(s):  
Kinase Activity ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Mitotic Exit ◽  
Cell Protein ◽  
Cell Axis ◽  
Pole Body ◽  
Catalytically Active ◽  
Surveillance Mechanism ◽  
Spindle Position

The spindle position checkpoint (SPOC) is an essential surveillance mechanism that allows mitotic exit only when the spindle is correctly oriented along the cell axis. Key SPOC components are the kinase Kin4 and the Bub2–Bfa1 GAP complex that inhibit the mitotic exit–promoting GTPase Tem1. During an unperturbed cell cycle, Kin4 associates with the mother spindle pole body (mSPB), whereas Bub2–Bfa1 is at the daughter SPB (dSPB). When the spindle is mispositioned, Bub2–Bfa1 and Kin4 bind to both SPBs, which enables Kin4 to phosphorylate Bfa1 and thereby block mitotic exit. Here, we show that the daughter cell protein Lte1 physically interacts with Kin4 and inhibits Kin4 kinase activity. Specifically, Lte1 binds to catalytically active Kin4 and promotes Kin4 hyperphosphorylation, which restricts Kin4 binding to the mSPB. This Lte1-mediated exclusion of Kin4 from the dSPB is essential for proper mitotic exit of cells with a correctly aligned spindle. Therefore, Lte1 promotes mitotic exit by inhibiting Kin4 activity at the dSPB.

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