PRP4 is a spindle assembly checkpoint protein required for MPS1, MAD1, and MAD2 localization to the kinetochores

The spindle checkpoint delays anaphase onset until every chromosome kinetochore has been efficiently captured by the mitotic spindle microtubules. In this study, we report that the human pre–messenger RNA processing 4 (PRP4) protein kinase associates with kinetochores during mitosis. PRP4 depletion by RNA interference induces mitotic acceleration. Moreover, we frequently observe lagging chromatids during anaphase leading to aneuploidy. PRP4-depleted cells do not arrest in mitosis after nocodazole treatment, indicating a spindle assembly checkpoint (SAC) failure. Thus, we find that PRP4 is necessary for recruitment or maintenance of the checkpoint proteins MPS1, MAD1, and MAD2 at the kinetochores. Our data clearly identify PRP4 as a previously unrecognized kinetochore component that is necessary to establish a functional SAC.

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Mitotic Spindle Assembly Checkpoint Protein MAD2B

10.32388/ndmy7q ◽

2020 ◽

Author(s):

Keyword(s):

Mitotic Spindle ◽

Spindle Assembly Checkpoint ◽

Spindle Assembly ◽

Checkpoint Protein ◽

Mitotic Spindle Assembly ◽

Spindle Assembly Checkpoint Protein

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The BUBR1 pseudokinase domain promotes efficient kinetochore PP2A-B56 recruitment to regulate spindle checkpoint silencing and chromosome alignment

10.1101/733378 ◽

2019 ◽

Author(s):

Luciano Gama Braga ◽

Angel F. Cisneros ◽

Michelle Mathieu ◽

Maxime Clerc ◽

Pauline Garcia ◽

...

Keyword(s):

Mitotic Spindle ◽

Spindle Assembly Checkpoint ◽

Spindle Assembly ◽

Aurora B ◽

Dependent Manner ◽

Regulatory Domain ◽

Checkpoint Protein ◽

Major Player ◽

Chromosome Alignment ◽

Spindle Assembly Checkpoint Protein

ABSTRACTThe balance of phospho-signalling at outer-kinetochores during mitosis is critical for the accurate attachments between kinetochores and the mitotic spindle and timely exit from mitosis. In humans, a major player in determining this balance is the PP2A-B56 phosphatase which is recruited to the Kinase Attachment Regulatory Domain (KARD) of the Spindle Assembly Checkpoint protein Budding Uninhibited by Benzimidazole 1-related 1 (BUBR1) in a phospho-dependent manner. This event unleashes a rapid, switch-like phosphatase relay that reverses phosphorylation at the kinetochore, extinguishing the checkpoint and promoting anaphase entry. Here, we conclusively demonstrate that the pseudokinase domain of human BUBR1 lacks phosphotransfer activity and that it was maintained in vertebrates because it allosterically promotes KARD phosphorylation. Mutation or removal of this domain results in decreased PP2A-B56 recruitment to the outer kinetochore, attenuated checkpoint silencing and errors in chromosome alignment as a result of imbalance in Aurora B activity. We demonstrate that the functions of the BUBR1 pseudokinase and the BUB1 kinase domains are intertwined, providing an explanation for retention of the pseudokinase domain in certain eukaryotes.

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Mitotic Spindle Assembly Checkpoint Protein MAD2A

10.32388/n6vlx4 ◽

2020 ◽

Author(s):

Keyword(s):

Mitotic Spindle ◽

Spindle Assembly Checkpoint ◽

Spindle Assembly ◽

Checkpoint Protein ◽

Mitotic Spindle Assembly ◽

Spindle Assembly Checkpoint Protein

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Centromeric CENP-A loading requires accurate mitotic timing, which is linked to checkpoint proteins

10.1101/394981 ◽

2018 ◽

Author(s):

Anne Laure Pauleau ◽

Andrea Bergner ◽

Janko Kajtez ◽

Sylvia Erhardt

Keyword(s):

Cell Cycle ◽

Spindle Assembly Checkpoint ◽

Cultured Cells ◽

Histone H3 ◽

Spindle Assembly ◽

Checkpoint Proteins ◽

Checkpoint Protein ◽

Histone H3 Variant ◽

Metaphase Stage ◽

Spindle Assembly Checkpoint Protein

AbstractA defining feature of centromeres is the presence of the histone H3 variant CENP-A that replaces H3 in a subset of centromeric nucleosomes. In Drosophila cultured cells CENP-A deposition at centromeres takes place during the metaphase stage of the cell cycle and strictly depends on the presence of its specific chaperone CAL1. How CENP-A loading is restricted to mitosis is unknown. We found that overexpression of CAL1 is associated with increased CENP-A levels at centromeres and completely uncouples CENP-A loading from mitosis. Moreover, CENP-A levels inversely correlate with mitosis duration. We found that CAL1 interacts with the spindle assembly checkpoint protein and RZZ complex component Zw10 and thus constitutes the anchor for the recruitment of RZZ. Therefore, CAL1 controls CENP-A incorporation at centromeres both quantitatively and temporally, connecting it to the spindle assembly checkpoint to ensure mitotic fidelity.

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The Human Spindle Assembly Checkpoint Protein Bub3 Is Required for the Establishment of Efficient Kinetochore–Microtubule Attachments

Molecular Biology of the Cell ◽

10.1091/mbc.e07-07-0633 ◽

2008 ◽

Vol 19 (4) ◽

pp. 1798-1813 ◽

Cited By ~ 64

Author(s):

Elsa Logarinho ◽

Tatiana Resende ◽

Cláudia Torres ◽

Hassan Bousbaa

Keyword(s):

Spindle Assembly Checkpoint ◽

Spindle Assembly ◽

Checkpoint Proteins ◽

Anaphase Onset ◽

Chromosome Congression ◽

The Status ◽

Chromosome Attachment ◽

High Resolution Microscopy ◽

Spindle Assembly Checkpoint Protein

The spindle assembly checkpoint monitors the status of kinetochore–microtubule (K-MT) attachments and delays anaphase onset until full metaphase alignment is achieved. Recently, the role of spindle assembly checkpoint proteins was expanded with the discovery that BubR1 and Bub1 are implicated in the regulation of K-MT attachments. One unsolved question is whether Bub3, known to form cell cycle constitutive complexes with both BubR1 and Bub1, is also required for proper chromosome-to-spindle attachments. Using RNA interference and high-resolution microscopy, we analyzed K-MT interactions in Bub3-depleted cells and compared them to those in Bub1- or BubR1-depleted cells. We found that Bub3 is essential for the establishment of correct K-MT attachments. In contrast to BubR1 depletion, which severely compromises chromosome attachment and alignment, we found Bub3 and Bub1 depletions to produce defective K-MT attachments that, however, still account for significant chromosome congression. After Aurora B inhibition, alignment defects become severer in Bub3- and Bub1-depleted cells, while partially rescued in BubR1-depleted cells, suggesting that Bub3 and Bub1 depletions perturb K-MT attachments distinctly from BubR1. Interestingly, misaligned chromosomes in Bub3- and Bub1-depleted cells were found to be predominantly bound in a side-on configuration. We propose that Bub3 promotes the formation of stable end-on bipolar attachments.

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