Faculty Opinions recommendation of Spindle checkpoint proteins and chromosome-microtubule attachment in budding yeast.

2004 ◽  
Author(s):  
Kevin Hardwick
Keyword(s):  
Budding Yeast ◽  
Spindle Checkpoint ◽  
Checkpoint Proteins ◽  
Microtubule Attachment

scholarly journals Spindle checkpoint proteins and chromosome–microtubule attachment in budding yeast

2004 ◽  
Vol 164 (4) ◽  
pp. 535-546 ◽  
Author(s):  
Emily S. Gillett ◽  
Christopher W. Espelin ◽  
Peter K. Sorger
Keyword(s):  
Mammalian Cells ◽  
Budding Yeast ◽  
Spindle Checkpoint ◽  
Evolutionary Divergence ◽  
Animal Cells ◽  
Checkpoint Proteins ◽  
Microtubule Attachment ◽  
The Status ◽  
Assembly Pathways ◽  
Normal Cell Cycle

Accurate chromosome segregation depends on precise regulation of mitosis by the spindle checkpoint. This checkpoint monitors the status of kinetochore–microtubule attachment and delays the metaphase to anaphase transition until all kinetochores have formed stable bipolar connections to the mitotic spindle. Components of the spindle checkpoint include the mitotic arrest defective (MAD) genes MAD1–3, and the budding uninhibited by benzimidazole (BUB) genes BUB1 and BUB3. In animal cells, all known spindle checkpoint proteins are recruited to kinetochores during normal mitoses. In contrast, we show that whereas Saccharomyces cerevisiae Bub1p and Bub3p are bound to kinetochores early in mitosis as part of the normal cell cycle, Mad1p and Mad2p are kinetochore bound only in the presence of spindle damage or kinetochore lesions that interfere with chromosome–microtubule attachment. Moreover, although Mad1p and Mad2p perform essential mitotic functions during every division cycle in mammalian cells, they are required in budding yeast only when mitosis goes awry. We propose that differences in the behavior of spindle checkpoint proteins in animal cells and budding yeast result primarily from evolutionary divergence in spindle assembly pathways.

scholarly journals MAD1-dependent recruitment of CDK1-CCNB1 to kinetochores promotes spindle checkpoint signaling

2019 ◽  
Vol 218 (4) ◽  
pp. 1108-1117 ◽  
Author(s):  
Tatiana Alfonso-Pérez ◽  
Daniel Hayward ◽  
James Holder ◽  
Ulrike Gruneberg ◽  
Francis A. Barr
Keyword(s):  
Feedback Loop ◽  
Spindle Checkpoint ◽  
Mitotic Exit ◽  
Checkpoint Signaling ◽  
Checkpoint Proteins ◽  
Mitotic Entry ◽  
Upstream Regulator ◽  
Microtubule Attachment ◽  
Integral Component ◽  
Checkpoint Pathway

Cyclin B–dependent kinase (CDK1-CCNB1) promotes entry into mitosis. Additionally, it inhibits mitotic exit by activating the spindle checkpoint. This latter role is mediated through phosphorylation of the checkpoint kinase MPS1 and other spindle checkpoint proteins. We find that CDK1-CCNB1 localizes to unattached kinetochores and like MPS1 is lost from these structures upon microtubule attachment. This suggests that CDK1-CCNB1 is an integral component and not only an upstream regulator of the spindle checkpoint pathway. Complementary proteomic and cell biological analysis demonstrate that the spindle checkpoint protein MAD1 is one of the major components of CCNB1 complexes, and that CCNB1 is recruited to unattached kinetochores in an MPS1-dependent fashion through interaction with the first 100 amino acids of MAD1. This MPS1 and MAD1-dependent pool of CDK1-CCNB1 creates a positive feedback loop necessary for timely recruitment of MPS1 to kinetochores during mitotic entry and for sustained spindle checkpoint arrest. CDK1-CCNB1 is therefore an integral component of the spindle checkpoint, ensuring the fidelity of mitosis.

scholarly journals MAD3 Encodes a Novel Component of the Spindle Checkpoint Which Interacts with Bub3p, Cdc20p, and Mad2p

2000 ◽  
Vol 148 (5) ◽  
pp. 871-882 ◽  
Author(s):  
Kevin G. Hardwick ◽  
Raymond C. Johnston ◽  
Dana L. Smith ◽  
Andrew W. Murray
Keyword(s):  
Cell Cycle ◽  
Sequence Analysis ◽  
Protein Kinase ◽  
Nuclear Protein ◽  
Budding Yeast ◽  
Spindle Checkpoint ◽  
Terminal Region ◽  
Loss Of Function ◽  
Checkpoint Proteins ◽  
Two Hybrid

We show that MAD3 encodes a novel 58-kD nuclear protein which is not essential for viability, but is an integral component of the spindle checkpoint in budding yeast. Sequence analysis reveals two regions of Mad3p that are 46 and 47% identical to sequences in the NH2-terminal region of the budding yeast Bub1 protein kinase. Bub1p is known to bind Bub3p (Roberts et al. 1994) and we use two-hybrid assays and coimmunoprecipitation experiments to show that Mad3p can also bind to Bub3p. In addition, we find that Mad3p interacts with Mad2p and the cell cycle regulator Cdc20p. We show that the two regions of homology between Mad3p and Bub1p are crucial for these interactions and identify loss of function mutations within each domain of Mad3p. We discuss roles for Mad3p and its interactions with other spindle checkpoint proteins and with Cdc20p, the target of the checkpoint.

scholarly journals Two Complexes of Spindle Checkpoint Proteins Containing Cdc20 and Mad2 Assemble during Mitosis Independently of the Kinetochore in Saccharomyces cerevisiae

2005 ◽  
Vol 4 (5) ◽  
pp. 867-878 ◽  
Author(s):  
Atasi Poddar ◽  
P. Todd Stukenberg ◽  
Daniel J. Burke
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Budding Yeast ◽  
Spindle Checkpoint ◽  
Anaphase Promoting Complex ◽  
Checkpoint Activation ◽  
Checkpoint Signaling ◽  
Checkpoint Proteins ◽  
In Cells

ABSTRACT Favored models of spindle checkpoint signaling propose that two inhibitory complexes (Mad2-Cdc20 and Mad2-Mad3-Bub3-Cdc20) must be assembled at kinetochores in order to inhibit mitosis. We have directly tested this model in the budding yeast Saccharomyces cerevisiae. The proteins Mad2, Mad3, Bub3, Cdc20, and Cdc27 in yeast were quantified, and there are sufficient amounts to form stoichiometric inhibitors of Cdc20 and the anaphase-promoting complex. Mad2 is present in two separate complexes in cells arrested in mitosis with nocodazole. There is a small amount of Mad2-Mad3-Bub3-Cdc20 and a much larger amount of a complex that contains Mad2-Cdc20. We use conditional mutants to show that both Mad2 and Mad3 are essential for establishment and maintenance of the spindle checkpoint. Both spindle checkpoint complexes containing Mad2 form in mitosis, not in response to checkpoint activation. The kinetochore is not required to form either complex. We propose that the conversion of Mad1-Mad2 to Cdc20-Mad2, a key step in generating inhibitory checkpoint complexes, is limited to mitosis by the availability of Cdc20 and is kinetochore independent.

scholarly journals Different spindle checkpoint proteins monitor microtubule attachment and tension at kinetochores inDrosophilacells

2004 ◽  
Vol 117 (9) ◽  
pp. 1757-1771 ◽  
Author(s):  
Elsa Logarinho ◽  
Hassan Bousbaa ◽  
José Miguel Dias ◽  
Carla Lopes ◽  
Isabel Amorim ◽  
...  
Keyword(s):  
Spindle Checkpoint ◽  
Checkpoint Proteins ◽  
Microtubule Attachment

scholarly journals The Spindle Checkpoint of Budding Yeast Depends on a Tight Complex between the Mad1 and Mad2 Proteins

1999 ◽  
Vol 10 (8) ◽  
pp. 2607-2618 ◽  
Author(s):  
Rey-Huei Chen ◽  
D. Michelle Brady ◽  
Dana Smith ◽  
Andrew W. Murray ◽  
Kevin G. Hardwick
Keyword(s):  
Cell Cycle ◽  
Amino Acids ◽  
Mitotic Spindle ◽  
Mutational Analysis ◽  
Budding Yeast ◽  
Gel Filtration ◽  
Spindle Checkpoint ◽  
Spindle Assembly ◽  
Checkpoint Proteins ◽  
Sds Page

The spindle checkpoint arrests the cell cycle at metaphase in the presence of defects in the mitotic spindle or in the attachment of chromosomes to the spindle. When spindle assembly is disrupted, the budding yeast mad and bub mutants fail to arrest and rapidly lose viability. We have cloned the MAD2 gene, which encodes a protein of 196 amino acids that remains at a constant level during the cell cycle. Gel filtration and co-immunoprecipitation analyses reveal that Mad2p tightly associates with another spindle checkpoint component, Mad1p. This association is independent of cell cycle stage and the presence or absence of other known checkpoint proteins. In addition, Mad2p binds to all of the different phosphorylated isoforms of Mad1p that can be resolved on SDS-PAGE. Deletion and mutational analysis of both proteins indicate that association of Mad2p with Mad1p is critical for checkpoint function and for hyperphosphorylation of Mad1p.

scholarly journals Multiple assembly mechanisms anchor the KMN spindle checkpoint platform at human mitotic kinetochores

2015 ◽  
Vol 208 (2) ◽  
pp. 181-196 ◽  
Author(s):  
Soonjoung Kim ◽  
Hongtao Yu
Keyword(s):  
Spindle Checkpoint ◽  
Aurora B ◽  
Dependent Manner ◽  
Checkpoint Proteins ◽  
Multiple Strategies ◽  
Complete Inactivation ◽  
Microtubule Attachment ◽  
Ndc80 Complex ◽  
Spindle Microtubules ◽  
Multiple Assembly

During mitosis, the spindle checkpoint senses kinetochores not properly attached to spindle microtubules and prevents precocious sister-chromatid separation and aneuploidy. The constitutive centromere-associated network (CCAN) at inner kinetochores anchors the KMN network consisting of Knl1, the Mis12 complex (Mis12C), and the Ndc80 complex (Ndc80C) at outer kinetochores. KMN is a critical kinetochore receptor for both microtubules and checkpoint proteins. Here, we show that nearly complete inactivation of KMN in human cells through multiple strategies produced strong checkpoint defects even when all kinetochores lacked microtubule attachment. These KMN-inactivating strategies reveal multiple KMN assembly mechanisms at human mitotic kinetochores. In one mechanism, the centromeric kinase Aurora B phosphorylates Mis12C and strengthens its binding to the CCAN subunit CENP-C. In another, CENP-T contributes to KMN attachment in a CENP-H-I-K–dependent manner. Our study provides insights into the mechanisms of mitosis-specific assembly of the checkpoint platform KMN at human kinetochores.

scholarly journals Distinct Chromosome Segregation Roles for Spindle Checkpoint Proteins

2002 ◽  
Vol 13 (9) ◽  
pp. 3029-3041 ◽  
Author(s):  
Cheryl D. Warren ◽  
D. Michelle Brady ◽  
Raymond C. Johnston ◽  
Joseph S. Hanna ◽  
Kevin G. Hardwick ◽  
...  
Keyword(s):  
Amino Acid ◽  
Chromosome Segregation ◽  
Chromosome Instability ◽  
Spindle Checkpoint ◽  
Adjacent Segment ◽  
Effect Analysis ◽  
Checkpoint Proteins ◽  
Chromosome Transmission ◽  
Acid Fragment ◽  
Molecular Functions

The spindle checkpoint plays a central role in the fidelity of chromosome transmission by ensuring that anaphase is initiated only after kinetochore-microtubule associations of all sister chromatid pairs are complete. In this study, we find that known spindle checkpoint proteins do not contribute equally to chromosome segregation fidelity in Saccharomyces cerevisiae. Loss of Bub1 or Bub3 protein elicits the largest effect. Analysis of Bub1p reveals the presence of two molecular functions. An N-terminal 608-amino acid (nonkinase) portion of the protein supports robust checkpoint activity, and, as expected, contributes to chromosome segregation. A C-terminal kinase-encoding segment independently contributes to chromosome segregation through an unknown mechanism. Both molecular functions depend on association with Bub3p. A 156-amino acid fragment of Bub1p functions in Bub3p binding and in kinetochore localization by one-hybrid assay. An adjacent segment is required for Mad1p binding, detected by deletion analysis and coimmunoprecipitation. Finally, overexpression of wild-type BUB1 or MAD3 genes leads to chromosome instability. Analysis of this activity indicates that the Bub3p-binding domain of Bub1p contributes to this phenotype through disruption of checkpoint activity as well as through introduction of kinetochore or spindle damage.

scholarly journals Cytoplasmic dynein participates in meiotic checkpoint inactivation in mouse oocytes by transporting cytoplasmic mitotic arrest-deficient (Mad) proteins from kinetochores to spindle poles

Reproduction ◽  
2007 ◽  
Vol 133 (4) ◽  
pp. 685-695 ◽  
Author(s):  
Dong Zhang ◽  
Shen Yin ◽  
Man-Xi Jiang ◽  
Wei Ma ◽  
Yi Hou ◽  
...  
Keyword(s):  
Spindle Checkpoint ◽  
Germinal Vesicle ◽  
Cytoplasmic Dynein ◽  
Mitotic Arrest ◽  
Checkpoint Proteins ◽  
Meiotic Progression ◽  
Spindle Poles ◽  
Anaphase Onset ◽  
Oocyte Meiosis ◽  
And Function

The present study was designed to investigate the localization and function of cytoplasmic dynein (dynein) during mouse oocyte meiosis and its relationship with two major spindle checkpoint proteins, mitotic arrest-deficient (Mad) 1 and Mad2. Oocytes at various stages during the first meiosis were fixed and immunostained for dynein, Mad1, Mad2, kinetochores, microtubules, and chromosomes. Some oocytes were treated with nocodazole before examination. Anti-dynein antibody was injected into the oocytes at germinal vesicle (GV) stage before the examination of its effects on meiotic progression or Mad1 and Mad2 localization. Results showed that dynein was present in the oocytes at various stages from GV to metaphase II and the locations of Mad1 and Mad2 were associated with dynein’s movement. Both Mad1 and Mad2 had two existing states: one existed in the cytoplasm (cytoplasmic Mad1 or cytoplasmic Mad2), which did not bind to kinetochores, while the other bound to kinetochores (kinetochore Mad1 or kinetochore Mad2). The equilibrium between the two states varied during meiosis and/or in response to the changes of the connection between microtubules and kinetochores. Cytoplasmic Mad1 and Mad2 recruited to chromosomes when the connection between microtubules and chromosomes was destroyed. Inhibition of dynein interferes with cytoplasmic Mad1 and Mad2 transportation from chromosomes to spindle poles, thus inhibits checkpoint silence and delays anaphase onset. These results indicate that dynein may play a role in spindle checkpoint inactivation.

Sign in / Sign up

Export Citation Format

Share Document