Quantitative Phosphoproteomics reveals new roles for PP6 in chromosome condensation and segregation
Ontology highlight
ABSTRACT:
INSTRUMENT(S): Orbitrap Fusion, Q Exactive Plus
ORGANISM(S): Homo Sapiens (ncbitaxon:9606)
SUBMITTER: Arminja Kettenbach
PROVIDER: MSV000079201 | MassIVE | Mon Jul 27 12:56:00 BST 2015
SECONDARY ACCESSION(S): PXD002609
REPOSITORIES: MassIVE
Similar Datasets
Project description:The segregation of maternal centromeres away from the paternal ones during the first division of meiosis depends on the attachment of sister kinetochores to microtubules emanating from the same spindle pole. In budding yeast monopolar attachment requires the recruitment to kinetochores of a protein complex called monopolin. The biochemical function of monopolin was unknown. Here, we have identified the casein kinase I Hrr25 as a hitherto unknown subunit of monopolin. Hrr25 differs from other monopolin components by its enzymatic activity and strong evolutionary conservation. We demonstrate that Hrr25’s kinase activity and its interaction with monopolin are both required for monopolar attachment. Accordingly, Hrr25 is associated with centromeres in meiosis I. Our results revealed a surprising new role for casein kinases and provide a hypothesis for the mechanism of monopolar attachment during meiosis I in sexually reproducing organisms: casein kinase I-dependent phosphorylation of kinetochore proteins. Keywords: ChIP-chip, Meiosis, Cell cycle, Saccharomyces cerevisiae, Chromosome VI tiling array, Hrr25, Mam1
2006-09-23 | GSE4792 | GEO
Project description:Chromosome segregation and cleavage plane determination involves the generation of pulling forces on microtubules that extend from the centrosomes to the cell cortex. These forces depend on cortical anchoring of the cytoplasmic dynein motor by a conserved ternary complex of Galpha, GPR-1/2, and LIN-5 proteins in C. elegans (Galpha-LGN-NuMA in mammals). Previously, we showed that the polarity kinase PKC-3 phosphorylates LIN-5 to control spindle positioning in early C. elegans embryos. Here, we investigate whether additional LIN-5 phosphorylations regulate cortical pulling forces, making use of targeted alteration of in vivo phosphorylated residues by CRISPR/Cas9-mediated genetic engineering. Four distinct in vivo phosphorylated LIN-5 residues were found to have critical functions in spindle positioning. Two of these residues form part of a 30 amino acid binding site for GPR-1, which we identified by reverse two-hybrid screening. We provide evidence for a dualkinase mechanism, involving GSK3 phosphorylation of S659 followed by phosphorylation of S662 by casein kinase 1. These LIN-5 phosphorylations promote LIN-5-GPR-1/2 interaction and contribute to cortical pulling forces. The other two critical residues, T168 and T181, form part of a cyclin-dependent kinase consensus site and are phosphorylated by CDK1-Cyclin B in vitro. We applied a novel strategy to characterize early embryonic defects in lethal T168/T181 knockin substitution mutants, and provide evidence for sequential LIN-5 N-terminal phosphorylation and dephosphorylation in dynein recruitment. Our data support that phosphorylation of multiple LIN-5 domains by different kinases contributes to a mechanism for spatiotemporal control of spindle positioning and chromosome segregation.
2018-10-26 | PXD004906 | Pride
Project description:The Saccharomyces cerevisiae Slx5/8 complex is the founding member of a recently defined class of ubiquitin ligases (STUbLs) that target sumoylated substrates. Slx5/8 has been implicated in genome stability and transcription, but the precise contribution to these processes is not clear. To characterize Slx5/8 function, we determined genome-wide changes in gene expression upon loss of either subunit. The majority of mRNA changes are part of a general stress response, also exhibited by mutants of other genome integrity pathways and therefore indicative of an indirect effect on transcription. Genome-wide binding analysis reveals a uniquely centromeric location for Slx5. Detailed phenotype analyses of slx5D and slx8D mutants show severe mitotic defects that include aneuploidy, spindle mispositioning, fish hook spindles and aberrant spindle kinetics. This is associated with accumulation of the PP2A regulatory subunit Rts1 at centromeres prior to entry into anaphase. Knockdown of the human STUbL orthologue RNF4 also results in chromosome segregation defects due to formation of chromosome bridges. The study shows that STUbLs have a conserved role in maintenance of chromosomal stability and the results link SUMO-dependent ubiquitination to a centromere-specific function during mitosis.
2013-08-06 | GSE33929 | GEO
Project description:Tumors that overexpress the MYC oncogene frequently demonstrate aneuploidy, numerical chromosome alterations associated with highly aggressive cancers, rapid tumor evolution, and poor patient outcome. Here, we identify that MYC overexpression induces defects in microtubule nucleation and mitotic spindle assembly, promoting chromosome segregation defects, micronuclei and chromosomal instability (CIN). High TPX2 expression is permissive for mitotic spindle assembly and chromosome segregation in cells with MYC overexpression; whereas TPX2 depletion blocks mitotic progression, induces cell death and prevents tumor growth. Attenuating MYC expression reverses mitotic defects, even in established tumor cell lines, implicating an ongoing role for high MYC in the persistence of CIN in tumors. Our studies implicate the MYC oncogene as a regulator of spindle assembly and identify a new MYC-TPX2 synthetic-lethal interaction that could represent a future therapeutic strategy in MYC-overexpressing cancers. Moreover, our studies suggest that blocking MYC activity can attenuate the emergence of CIN and tumor evolution.
2020-03-30 | GSE130921 | GEO
Project description:Tumors that overexpress the MYC oncogene frequently demonstrate aneuploidy, numerical chromosome alterations associated with highly aggressive cancers, rapid tumor evolution, and poor patient outcome. Here, we identify that MYC overexpression induces defects in microtubule nucleation and mitotic spindle assembly, promoting chromosome segregation defects, micronuclei and chromosomal instability (CIN). High TPX2 expression is permissive for mitotic spindle assembly and chromosome segregation in cells with MYC overexpression; whereas TPX2 depletion blocks mitotic progression, induces cell death and prevents tumor growth. Attenuating MYC expression reverses mitotic defects, even in established tumor cell lines, implicating an ongoing role for high MYC in the persistence of CIN in tumors. Our studies implicate the MYC oncogene as a regulator of spindle assembly and identify a new MYC-TPX2 synthetic-lethal interaction that could represent a future therapeutic strategy in MYC-overexpressing cancers. Moreover, our studies suggest that blocking MYC activity can attenuate the emergence of CIN and tumor evolution.
2020-03-30 | GSE130920 | GEO
Project description:Proper centrosome movement to the bipolar position is a prerequisite for bipolar spindle orientation and genome stability. Polo like kinase 1 (Plk1) is a key mitotic kinase which controls centrosome separation. Here we found that Plk1 phosphorylated residue Thr76 in VCP/p97, an AAA-ATPase mainly involved in protein homeostasis, at centrosome from prophase to anaphase. This phosphorylation recruited VCP to centrosome to regulate centrosome orientation. VCP also exhibited strong co-localization with Eg5, a mitotic kinesin motor for centrosome movement, at mitotic spindle, and dephosphorylation of Thr76 in VCP was required for the enrichment of VCP and Eg5 to the spindle, thus, ensuring proper spindle orientation and chromosome segregation. Since genome instability is the hallmark of cancer and the phosphorylation of Thr76 in VCP is important for proper centrosome movement, spindle orientation, and chromosome segregation, we, thus, knocked down VCP in MDA-MB-231cells by its specific shRNA, and reconstituted the expression of VCP by infecting the cells with lentivirus encoding shRNA-resistant Flag-VCPWT or Flag-VCPT76A. We then implanted VCPWT- or VCPT76A-expressing MDA-MB-231 cells into nude mice and found that the tumor growth in mice implanted with VCPT76A-expressing cells was significantly slower when compared with the mice implanted with the Flag-VCPWT-expressing cells. To better understand the decreased tumor formation ability of Flag-VCPT76A-expressing cells, we isolated the primary breast tumor tissues for the RNA-Seq analysis. Of the 57,905 mapped whole genome genes in the isolated tumors, we identified 234 differentially expressed genes (DEGs; false discovery rate (FDR) < 0.1).
2020-03-28 | GSE147636 | GEO
Project description:The Greatwall/Mastl kinase is an essential gene, which regulates the phosphatase activity that counteracts the phosphorylation of Cdk1 substrates. Although Mastl-/- MEFs can enter mitosis, they are unable to complete mitosis due to chromosome segregation defects. Here, we show that Mastl is essential for robust spindle assembly checkpoint (SAC) maintenance. Mastl-/- MEFs display reduced phosphorylation and kinase activity of MPS1, which causes mislocalization of MPS1, Mad1, and Aurora B from the kinetochore and the inner centromere regions. This results in premature inactivation of SAC signalling and early anaphase onset without correction of chromosome-spindle attachment mistakes. Treatment of the knockout cells with protein phosphatase II inhibitor okadaic acid (OA) rescued decreased MPS1 activity, mislocalization of Aurora B, Mad1, MPS1, and premature mitotic slippage. Our data demonstrates how regulation of PP2A activity by Mastl kinase prevents premature SAC silencing as a result of controlling the phosphorylation status and activity of MPS1.
2018-10-26 | PXD004882 | Pride
Project description:Kinetochores are multiprotein assemblies that bind chromosomes to the spindle during mitosis. Despite conserved roles, repertoires of kinetochore proteins vary greatly across eukaryotes. In particular, most known components are not clearly detected in a group of parasites known as the Apicomplexa. Furthermore, flexibility in scale of amplification and an apparent incapability to delay cell cycle progression in response to spindle integrity has coined an idea these parasites divide in the absence of spindle checkpoints. In this study, we reunite divergent apicomplexan kinetochore components to a common eukaryotic set and additionally identify 9 kinetochore proteins that share little homology to known proteins. AKiTs are essential for chromosome segregation and show modes of division parallel to eukaryotic metaphase to anaphase transition and spindle assembly checkpoint signaling. These findings suggest conserved spindle assembly checkpoint signaling maintains fidelity during chromosome segregation in apicomplexan parasites.
2023-03-11 | PXD028595 | Pride
Project description:Correct chromosome segregation during cell division depends on proper connections between spindle microtubules and kinetochores. During prometaphase, kinetochores are temporarily covered with a dense protein meshwork known as the fibrous corona. Formed by oligomerization of ROD/ZW10/ZWILCH-SPINDLY (RZZ-S) complexes, the fibrous corona promotes spindle assembly, chromosome orientation and spindle checkpoint signaling. The molecular requirements for formation of the fibrous corona are not fully understood. Here we show that the fibrous corona depends on the mitotic kinesin CENP-E, and that poorly expanded fibrous coronas after CENP-E depletion are functionally compromised. This previously unrecognized role for CENP-E does not require its motor activity but instead is driven by its C-terminal microtubule-binding region and farnesyl modification thereof. The ‘birth’ of a farnesylation motif in CENP-E orthologs during Obazoa evolution closely aligns with presence of the full RZZ-S module, and we show that in cells CENP-E interacts with RZZ-S complexes in a farnesyl-dependent manner. CENP-E is recruited to kinetochores following RZZ-S, and - while not required for RZZ-S oligomerization per se - promotes subsequent fibrous corona expansion. Our results show that proper spindle assembly has a non-motor contribution from the kinesin CENP-E through stabilization of the fibrous corona meshwork during its formation.
2023-10-09 | PXD040338 | Pride
Project description:The fidelity of chromosome duplication through cell divisions requires timely binding and release of the cohesin. Cohesin is a ring-shaped protein complex linking newly replicated sister chromatids to ensure their appropriate transmission through mitosis. Upon commencement of mitosis cohesin is removed from DNA in two steps: first, from chromosome arms resulting in sister chromatid resolution, and, second, from centromers leading to sister chromatid segregation. As DNA of eukaryotic chromosomes is assembled into chromatin, regulation of sister chromatid cohesion-segregation may involve chromatin modifying machinery, but this link is not well understood. Here we report that H2A-H2B histone chaperone NAP1, a factor, which is primarily implicated in chromatin assembly, is required for cohesin release from mitotic chromosome arms. NAP1 and cohesin protein complex interact directly and share multiple binding sites on chromatin. Depletion of the NAP1 hinders cohesin removal during mitosis resulting in accumulation of unresolved sister chromatids. Thus, in addition to its well established functions in chromatin dynamics, histone chaperone NAP1 coordinates cell cycle dependent cohesin release. These results reveal a novel molecular pathway for sister chromatid resolution and emphasizes a role for histone chaperones in control of eukaryotic genome replication and transmission. Genome-wide NAP1 and Cohesin ChIP-chip profiling in Drosophila S2 cells. The supplementary bed file S2_cohesin_sites.bed contains cohesin binding sites obtained by intersecting the sets of significant ChIP-chip peaks for SA (a cohesin subunit; stromalin) and SMC1.
2012-07-25 | E-GEOD-30938 | biostudies-arrayexpress