Signalling dynamics in the spindle checkpoint response

London, Nitobe; Biggins, Sue

doi:10.1038/nrm3888

Cited by 299 publications

(315 citation statements)

References 150 publications

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“…The spindle checkpoint senses the existence of kinetochores not attached or improperly attached to spindle microtubules and inhibits APC/C Cdc20 through promoting the formation of the APC/C-inhibitory mitotic checkpoint complex (MCC) consisting of BubR1, Bub3, mitotic arrest deficient 2 (Mad2), and Cdc20 (8)(9)(10)(11)(12). APC/C inhibition delays separase activation, cohesin cleavage, and the onset of chromosome segregation and provides time for unattached kinetochores to reach proper attachment before separation.…”

mentioning

confidence: 99%

Structure of an intermediate conformer of the spindle checkpoint protein Mad2

Hara

Özkan

Sun

et al. 2015

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

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The spindle checkpoint senses unattached kinetochores during prometaphase and inhibits the anaphase-promoting complex or cyclosome (APC/C), thus ensuring accurate chromosome segregation. The checkpoint protein mitotic arrest deficient 2 (Mad2) is an unusual protein with multiple folded states. Mad2 adopts the closed conformation (C-Mad2) in a Mad1–Mad2 core complex. In mitosis, kinetochore-bound Mad1–C-Mad2 recruits latent, open Mad2 (O-Mad2) from the cytosol and converts it to an intermediate conformer (I-Mad2), which can then bind and inhibit the APC/C activator cell division cycle 20 (Cdc20) as C-Mad2. Here, we report the crystal structure and NMR analysis of I-Mad2 bound to C-Mad2. Although I-Mad2 retains the O-Mad2 fold in crystal and in solution, its core structural elements undergo discernible rigid-body movements and more closely resemble C-Mad2. Residues exhibiting methyl chemical shift changes in I-Mad2 form a contiguous, interior network that connects its C-Mad2–binding site to the conformationally malleable C-terminal region. Mutations of residues at the I-Mad2–C-Mad2 interface hinder I-Mad2 formation and impede the structural transition of Mad2. Our study provides insight into the conformational activation of Mad2 and establishes the basis of allosteric communication between two distal sites in Mad2.

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confidence: 99%

Structure of an intermediate conformer of the spindle checkpoint protein Mad2

Hara

Özkan

Sun

et al. 2015

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

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“…Mad1-Mad2 first catalyzes MCC assembly at interphase nuclear pores [3], then migrates to kinetochores at nuclear envelope breakdown (NEBD) and resumes MCC assembly until bipolar spindle attachment is complete [1,2]. There is significant debate about the factor(s) involved in targeting Mad1-Mad2 to kinetochores in higher eukaryotes [4][5][6][7][8][9].…”

Section: Discussionmentioning

confidence: 99%

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confidence: 99%

The RZZ complex integrates spindle checkpoint maintenance with dynamic expansion of unattached kinetochores

Rodriguez-Rodriguez

McKinley

Sikirzhytski

et al. 2018

Preprint

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SummaryThe Mad1-Mad2 heterodimer is the catalytic hub of the spindle assembly checkpoint (SAC), which controls mitosis through assembly of a multi-subunit anaphase inhibitor, the mitotic checkpoint complex (MCC) [1,2]. Mad1-Mad2 first catalyzes MCC assembly at interphase nuclear pores [3], then migrates to kinetochores at nuclear envelope breakdown (NEBD) and resumes MCC assembly until bipolar spindle attachment is complete [1,2]. There is significant debate about the factor(s) involved in targeting Mad1-Mad2 to kinetochores in higher eukaryotes [4][5][6][7][8][9]. Through gene editing and livecell imaging, we found that the human Rod-Zw10-Zwilch (RZZ) complex is dispensable for cell viability and initial recruitment of Mad1-Mad2 to kinetochores at NEBD, but then becomes necessary to tether Mad1-Mad2 at kinetochores and sustain SAC arrest in cells challenged with spindle poisons. We also show that RZZ forms the mesh-like fibrous corona, a structural expansion of the outer kinetochore important for timely chromosome congression [10][11][12][13] once Mps1 phosphorylates the N-terminus of Rod.Artificially tethering Mad1-Mad2 to kinetochores enabled long-term mitotic arrest in the absence of RZZ. Conversely, blocking early RZZ-independent recruitment of Mad1-Mad2 eliminated the transient SAC response in RZZ-null cells. We conclude that RZZ drives structural changes in the outer kinetochore that facilitate chromosome biorientation and chronic SAC transduction, a key determinant of cytotoxicity during antimitotic drug therapy [14][15][16].All rights reserved. No reuse allowed without permission.was not peer-reviewed) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity.The copyright holder for this preprint (which . http://dx.doi.org/10.1101/297580 doi: bioRxiv preprint first posted online Apr. 9, 2018; 3 Results RZZ is required for long-term mitotic arrest in response to spindle poisonsRecent studies have reached different conclusions about the specific roles and relative importance of Bub1 and the RZZ complex in targeting Mad1-Mad2 to kinetochores and transducing SAC arrest [4][5][6][7][8]. To interrogate RZZ function with maximum penetrance, we used AAV (adeno-associated virus)-and CRISPR-mediated gene editing to target the KNTC1 (Rod) locus in HCT116 cells, a diploid colorectal cell line ( Fig. S1A-C). The resulting KNTC1 HF/-(hypomorph-flox) cells expressed Rod at ~20% of the wildtype level ( Fig. 1A-B and S1D) and exited mitosis prematurely when microtubule polymerization (nocodazole, 99 ± 6 min s.e.m.) or Eg5-dependent spindle bipolarity (S-trityl-L-cysteine (STLC), 193 ± 9 min s.e.m.) were inhibited, whereas wildtype cells never exited mitosis during the 16-hour timelapse (Fig. 1A-B). To determine if complete loss of the RZZ complex is compatible with clonogenic survival, KNTC1 HF/-cells were transduced with an adenovirus expressing Cre recombinase (AdCre) and subjected to limiting dilution.Unlike most SAC gene knockouts in mammals, KNTC1 -/-cells were viable (Fig. 1...

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“…The SAC is specifically activated at unattached kinetochores of misaligned chromosomes and produces a diffusible signal, which inhibits Cdc20, an essential co-activator of the anaphase-promoting complex/cyclosome (APC/C). [5][6][7][8][9][10] Thus, this system enables cells to delay the cell cycle until all kinetochores are attached to microtubules. Mad1, Mad2, Mad3/BubR1, Mps1, Bub1 and Bub3 are considered the core components of the SAC.…”

Section: Introductionmentioning

confidence: 99%

The spindle assembly checkpoint promotes chromosome bi-orientation: A novel Mad1 role in chromosome alignment

Akera

Watanabe

2016

Cell Cycle

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Faithful chromosome segregation relies on dynamic interactions between spindle microtubules and chromosomes. Especially, all chromosomes must be aligned at the equator of the spindle to establish biorientation before they start to segregate. The spindle assembly checkpoint (SAC) monitors this process, inhibiting chromosome segregation until all chromosomes achieve bi-orientation. The original concept of 'checkpoints' was proposed as an external surveillance system that does not play an active role in the process it monitors. However, accumulating evidence from recent studies suggests that SAC components do play an active role in chromosome bi-orientation. In this review, we highlight a novel Mad1 role in chromosome alignment, which is the first conserved mechanism that links the SAC and kinesin-mediated chromosome gliding.

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Signalling dynamics in the spindle checkpoint response

Cited by 299 publications

References 150 publications

Structure of an intermediate conformer of the spindle checkpoint protein Mad2

Structure of an intermediate conformer of the spindle checkpoint protein Mad2

The RZZ complex integrates spindle checkpoint maintenance with dynamic expansion of unattached kinetochores

The spindle assembly checkpoint promotes chromosome bi-orientation: A novel Mad1 role in chromosome alignment

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