scholarly journals Kinesin-Binding Protein (KBP) buffers the activity of KIF18A and KIF15 in mitosis to ensure accurate chromosome segregation

2018 ◽  
Author(s):  
Heidi L. H. Malaby ◽  
Megan E. Dumas ◽  
Ryoma Ohi ◽  
Jason Stumpff

ABSTRACTMitotic kinesins must be regulated to ensure a precise balance of spindle forces and accurate segregation of chromosomes into daughter cells. Here we demonstrate that Kinesin-Binding Protein (KBP) reduces the activity of KIF18A and KIF15 during metaphase. Overexpression of KBP disrupts the movement and alignment of mitotic chromosomes and decreases spindle length, a combination of phenotypes observed in cells deficient for KIF18A and KIF15, respectively. We show through gliding filament and microtubule co-pelleting assays that KBP directly inhibits KIF18A and KIF15 motor activity by preventing microtubule-binding. Consistent with these effects, the mitotic localizations of KIF18A and KIF15 are altered by overexpression of KBP. Cells depleted of KBP exhibit lagging chromosomes in anaphase, an effect that is recapitulated by KIF15 and KIF18A overexpression. Based on these data, we propose a model in which KBP acts as a protein buffer in mitosis, protecting cells from excessive KIF18A and KIF15 activity to promote accurate chromosome segregation.SUMMARYKinesin-Binding Protein (KBP) is identified as a regulator of the kinesins KIF18A and KIF15 during mitosis. KBP buffers the activity of these motors to control chromosome alignment and spindle integrity in metaphase and prevent lagging chromosomes in anaphase.

2019 ◽  
Vol 218 (4) ◽  
pp. 1218-1234 ◽  
Author(s):  
Heidi L.H. Malaby ◽  
Megan E. Dumas ◽  
Ryoma Ohi ◽  
Jason Stumpff

Mitotic kinesins must be regulated to ensure a precise balance of spindle forces and accurate segregation of chromosomes into daughter cells. Here, we demonstrate that kinesin-binding protein (KBP) reduces the activity of KIF18A and KIF15 during metaphase. Overexpression of KBP disrupts the movement and alignment of mitotic chromosomes and decreases spindle length, a combination of phenotypes observed in cells deficient for KIF18A and KIF15, respectively. We show through gliding filament and microtubule co-pelleting assays that KBP directly inhibits KIF18A and KIF15 motor activity by preventing microtubule binding. Consistent with these effects, the mitotic localizations of KIF18A and KIF15 are altered by overexpression of KBP. Cells depleted of KBP exhibit lagging chromosomes in anaphase, an effect that is recapitulated by KIF15 and KIF18A overexpression. Based on these data, we propose a model in which KBP acts as a protein buffer in mitosis, protecting cells from excessive KIF18A and KIF15 activity to promote accurate chromosome segregation.


2020 ◽  
pp. mbc.E20-09-0585
Author(s):  
Luciano Gama Braga ◽  
Diogjena Katerina Prifti ◽  
Chantal Garand ◽  
Pawan Kumar Saini ◽  
Sabine Elowe

Accurate chromosome alignment at metaphase facilitates the equal segregation of sister chromatids to each of the nascent daughter cells. Lack of proper metaphase alignment is an indicator of defective chromosome congression and aberrant kinetochore-microtubule attachments which in turn promotes chromosome missegregation and aneuploidy, hallmarks of cancer. Tools to sensitively, accurately and quantitatively measure chromosome alignment at metaphase will facilitate understanding of the contribution of chromosome segregation errors to the development of aneuploidy. In this work, we have developed and validated a method based on analytical geometry to measure several indicators of chromosome misalignment. We generated semi-automated and flexible ImageJ2/Fiji pipelines to quantify kinetochore misalignment at metaphase plates as well as lagging chromosomes at anaphase. These tools will ultimately allow sensitive and systematic quantitation of these chromosome segregation defects in cells undergoing mitosis.


2015 ◽  
Vol 211 (6) ◽  
pp. 1141-1156 ◽  
Author(s):  
Itaru Samejima ◽  
Christos Spanos ◽  
Flavia de Lima Alves ◽  
Tetsuya Hori ◽  
Marinela Perpelescu ◽  
...  

Kinetochores orchestrate mitotic chromosome segregation. Here, we use quantitative mass spectrometry of mitotic chromosomes isolated from a comprehensive set of chicken DT40 mutants to examine the dependencies of 93 confirmed and putative kinetochore proteins for stable association with chromosomes. Clustering and network analysis reveal both known and unexpected aspects of coordinated behavior for members of kinetochore protein complexes. Surprisingly, CENP-T depends on CENP-N for chromosome localization. The Ndc80 complex exhibits robust correlations with all other complexes in a “core” kinetochore network. Ndc80 associated with CENP-T interacts with a cohort of Rod, zw10, and zwilch (RZZ)–interacting proteins that includes Spindly, Mad1, and CENP-E. This complex may coordinate microtubule binding with checkpoint signaling. Ndc80 associated with CENP-C forms the KMN (Knl1, Mis12, Ndc80) network and may be the microtubule-binding “workhorse” of the kinetochore. Our data also suggest that CENP-O and CENP-R may regulate the size of the inner kinetochore without influencing the assembly of the outer kinetochore.


2020 ◽  
Author(s):  
Theodor Marsoner ◽  
Poornima Yedavalli ◽  
Chiara Masnovo ◽  
Katrin Schmitzer ◽  
Christopher S. Campbell

AbstractChromosome biorientation is established by the four-member chromosomal passenger complex (CPC) through phosphorylation of incorrect kinetochore-microtubule attachments. During chromosome alignment, the CPC localizes to the inner centromere, the inner kinetochore and spindle microtubules. Here we show that a small region of the CPC subunit INCENP/Sli15 is required to target the complex to all three of these locations in budding yeast. This region, the SAH, is essential for phosphorylation of outer kinetochore substrates, chromosome segregation, and viability. By restoring the CPC to each of these three locations individually, we found that inner centromere localization is sufficient to establish chromosome biorientation and viability independently of the other two targeting mechanisms. Remarkably, although neither the inner kinetochore nor microtubule binding activities was able to rescue viability individually, they were able to do so when combined. We have therefore identified two parallel pathways by which the CPC can promote chromosome biorientation and proper completion of mitosis.


2009 ◽  
Vol 284 (34) ◽  
pp. 23072-23082 ◽  
Author(s):  
Kai Yuan ◽  
Na Li ◽  
Kai Jiang ◽  
Tongge Zhu ◽  
Yuda Huo ◽  
...  

2019 ◽  
Author(s):  
Victoria Hassebroek ◽  
Hyewon Park ◽  
Nootan Pandey ◽  
Brooklyn T. Lerbakken ◽  
Vasilisa Aksenova ◽  
...  

AbstractPolo-like kinase interacting checkpoint helicase (PICH) is a SNF2 family DNA translocase and is a Small Ubiquitin-like modifier (SUMO) binding protein. Despite that both translocase activity and SUMO-binding activity are required for proper chromosome segregation, how these two activities function to mediate chromosome segregation remains unknown. Here, we show that PICH specifically promotes dissociation of SUMOylated TopoisomeraseIIα (TopoIIα) from mitotic chromosomes. When TopoIIα is stalled by treatment of cells with a potent TopoII inhibitor, ICRF-193, TopoIIα becomes SUMOylated, and this promotes its interaction with PICH. Conditional depletion of PICH using the Auxin Inducible Degron (AID) system resulted in retention of SUMOylated TopoIIα on chromosomes, indicating that PICH removes stalled SUMOylated TopoIIα from chromosomes. In vitro assays showed that PICH specifically regulates SUMOylated TopoIIα activity using its SUMO-binding and translocase activities. Taken together, we propose a novel mechanism for how PICH acts on stalled SUMOylated TopoIIα for proper chromosome segregation.Summary StatementPolo-like kinase interacting checkpoint helicase (PICH) interacts with SUMOylated proteins to mediate proper chromosome segregation during mitosis. The results demonstrate that PICH promotes dissociation of SUMOylated TopoisomeraseIIα from chromosomes and that function leads to proper chromosome segregation.


2020 ◽  
Vol 6 (1) ◽  
pp. 4
Author(s):  
Takashi Ideue ◽  
Tokio Tani

Chromosome segregation is strictly regulated for the proper distribution of genetic material to daughter cells. During this process, mitotic chromosomes are pulled to both poles by bundles of microtubules attached to kinetochores that are assembled on the chromosomes. Centromeres are specific regions where kinetochores assemble. Although these regions were previously considered to be silent, some experimental studies have demonstrated that transcription occurs in these regions to generate non-coding RNAs (ncRNAs). These centromeric ncRNAs (cenRNAs) are involved in centromere functions. Here, we describe the currently available information on the functions of cenRNAs in several species.


2020 ◽  
Vol 219 (11) ◽  
Author(s):  
Judith A. Sharp ◽  
Carlos Perea-Resa ◽  
Wei Wang ◽  
Michael D. Blower

During mitosis, the genome is transformed from a decondensed, transcriptionally active state to a highly condensed, transcriptionally inactive state. Mitotic chromosome reorganization is marked by the general attenuation of transcription on chromosome arms, yet how the cell regulates nuclear and chromatin-associated RNAs after chromosome condensation and nuclear envelope breakdown is unknown. SAF-A/hnRNPU is an abundant nuclear protein with RNA-to-DNA tethering activity, coordinated by two spatially distinct nucleic acid–binding domains. Here we show that RNA is evicted from prophase chromosomes through Aurora-B–dependent phosphorylation of the SAF-A DNA-binding domain; failure to execute this pathway leads to accumulation of SAF-A–RNA complexes on mitotic chromosomes, defects in metaphase chromosome alignment, and elevated rates of chromosome missegregation in anaphase. This work reveals a role for Aurora-B in removing chromatin-associated RNAs during prophase and demonstrates that Aurora-B–dependent relocalization of SAF-A during cell division contributes to the fidelity of chromosome segregation.


2018 ◽  
Author(s):  
Matthew P. Miller ◽  
Rena K. Evans ◽  
Alex Zelter ◽  
Elisabeth A. Geyer ◽  
Michael J. MacCoss ◽  
...  

ABSTRACTAccurate segregation of chromosomes to daughter cells is a critical aspect of cell division. It requires the kinetochores on duplicated chromosomes to biorient, attaching to microtubules from opposite poles of the cell. Bioriented attachments come under tension, while incorrect attachments lack tension and must be destabilized. A well-studied error correction pathway is mediated by the Aurora B kinase, which destabilizes low tension-bearing attachments. We recently discovered that in vitro, kinetochores display an additional intrinsic tension-sensing pathway that utilizes Stu2. This pathway’s contribution to error correction in cells, however, was unknown. Here, we identify a Stu2 mutant that abolishes its kinetochore function and show that it causes error correction defects in vivo. We also show that this intrinsic tension-sensing pathway functions in concert with the Aurora B-mediated pathway. Together, our work indicates that cells employ at least two pathways to ensure biorientation and the accuracy of chromosome segregation.


2016 ◽  
Vol 212 (5) ◽  
pp. 499-513 ◽  
Author(s):  
Liliane Christ ◽  
Eva M. Wenzel ◽  
Knut Liestøl ◽  
Camilla Raiborg ◽  
Coen Campsteijn ◽  
...  

Cytokinetic abscission, the final stage of cell division where the two daughter cells are separated, is mediated by the endosomal sorting complex required for transport (ESCRT) machinery. The ESCRT-III subunit CHMP4B is a key effector in abscission, whereas its paralogue, CHMP4C, is a component in the abscission checkpoint that delays abscission until chromatin is cleared from the intercellular bridge. How recruitment of these components is mediated during cytokinesis remains poorly understood, although the ESCRT-binding protein ALIX has been implicated. Here, we show that ESCRT-II and the ESCRT-II–binding ESCRT-III subunit CHMP6 cooperate with ESCRT-I to recruit CHMP4B, with ALIX providing a parallel recruitment arm. In contrast to CHMP4B, we find that recruitment of CHMP4C relies predominantly on ALIX. Accordingly, ALIX depletion leads to furrow regression in cells with chromosome bridges, a phenotype associated with abscission checkpoint signaling failure. Collectively, our work reveals a two-pronged recruitment of ESCRT-III to the cytokinetic bridge and implicates ALIX in abscission checkpoint signaling.


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