scholarly journals Molecular Basis for CPC-Sgo1 Interaction: Implications for Centromere Localisation and Function of the CPC

2021 ◽  
Author(s):  
Maria Alba Abad ◽  
Tanmay Gupta ◽  
Michael A Hadders ◽  
Amanda Meppelink ◽  
J Pepijn Wopken ◽  
...  
Keyword(s):  
Chromosome Segregation ◽  
Molecular Basis ◽  
Hot Spot ◽  
Histone H3 ◽  
Direct Interaction ◽  
Histone H2a ◽  
Chromosomal Passenger ◽  
And Function ◽  
Affinity Interaction

AbstractThe Chromosomal Passenger Complex (CPC; consisting of Borealin, Survivin, INCENP and Aurora B kinase) and Shugoshin 1 (Sgo1) are key regulators of chromosome bi-orientation, a process essential for error-free chromosome segregation. Their functions rely on their ability to associate with centromeres. Two histone phosphorylations, histone H3 Thr3 (H3T3ph; directly recognised by Survivin) and histone H2A Thr120 (H2AT120ph; indirectly recognised via Sgo1), together with CPC’s intrinsic ability to bind nucleosome, facilitate CPC centromere recruitment. The molecular basis for CPC-Sgo1 binding and how their direct interaction influences CPC centromere localisation and function are lacking. Here, using an integrative structure-function approach, we show that the histone H3-like Sgo1 N-terminal tail interacts with Survivin acting as a hot-spot for CPC-Sgo1 assembly, while downstream Sgo1 residues, mainly with Borealin contributes for high affinity interaction. Disruption of the Sgo1 N-terminal tail-Survivin interaction abolished CPC-Sgo1 assembly in vitro and perturbed centromere localisation and function of CPC. Our findings provide evidence that CPC binding to Sgo1 and histone H3 N-terminal tail are mutually exclusive, suggesting that these interactions will likely take place in a spatially/temporally restricted manner and provide a rationale for the Sgo1-mediated ‘kinetochore proximal centromere’ pool of CPC.

scholarly journals Phosphorylation-dependent interaction of the synaptic vesicle proteins cysteine string protein and synaptotagmin I

2002 ◽  
Vol 364 (2) ◽  
pp. 343-347 ◽  
Author(s):  
Gareth J.O. EVANS ◽  
Alan MORGAN
Keyword(s):  
Rat Brain ◽  
Direct Interaction ◽  
Secretory Vesicle ◽  
Brain Membrane ◽  
Synaptotagmin I ◽  
Phosphorylated Form ◽  
Order Of Magnitude ◽  
And Function

The secretory vesicle cysteine string proteins (CSPs) are members of the DnaJ family of chaperones, and function at late stages of Ca2+-regulated exocytosis by an unknown mechanism. To determine novel binding partners of CSPs, we employed a pull-down strategy from purified rat brain membrane or cytosolic proteins using recombinant hexahistidine-tagged (His6-)CSP. Western blotting of the CSP-binding proteins identified synaptotagmin I to be a putative binding partner. Furthermore, pull-down assays using cAMP-dependent protein kinase (PKA)-phosphorylated CSP recovered significantly less synaptotagmin. Complexes containing CSP and synaptotagmin were immunoprecipitated from rat brain membranes, further suggesting that these proteins interact in vivo. Binding assays in vitro using recombinant proteins confirmed a direct interaction between the two proteins and demonstrated that the PKA-phosphorylated form of CSP binds synaptotagmin with approximately an order of magnitude lower affinity than the non-phosphorylated form. Genetic studies have implicated each of these proteins in the Ca2+-dependency of exocytosis and, since CSP does not bind Ca2+, this novel interaction might explain the Ca2+-dependent actions of CSP.

scholarly journals A positive feedback mechanism ensures proper assembly of the functional inner centromere during mitosis in human cells

2018 ◽  
Vol 294 (5) ◽  
pp. 1437-1450 ◽  
Author(s):  
Cai Liang ◽  
Zhenlei Zhang ◽  
Qinfu Chen ◽  
Haiyan Yan ◽  
Miao Zhang ◽  
...  
Keyword(s):  
Positive Feedback ◽  
Histone H3 ◽  
Causal Link ◽  
Feedback Mechanism ◽  
Histone H2a ◽  
Defective Mutant ◽  
Chromosomal Passenger ◽  
Phosphatase 2A ◽  
Elevated Rate ◽  
Positive Feedback Mechanism

The inner centromere region of a mitotic chromosome critically regulates sister chromatid cohesion and kinetochore–microtubule attachments. However, the molecular mechanism underlying inner centromere assembly remains elusive. Here, using CRISPR/Cas9-based gene editing in HeLa cells, we disrupted the interaction of Shugoshin 1 (Sgo1) with histone H2A phosphorylated on Thr-120 (H2ApT120) to selectively release Sgo1 from mitotic centromeres. Interestingly, cells expressing the H2ApT120-binding defective mutant of Sgo1 have an elevated rate of chromosome missegregation accompanied by weakened centromeric cohesion and decreased centromere accumulation of the chromosomal passenger complex (CPC), an integral part of the inner centromere and a key player in the correction of erroneous kinetochore–microtubule attachments. When artificially tethered to centromeres, a Sgo1 mutant defective in binding protein phosphatase 2A (PP2A) is not able to support proper centromeric cohesion and CPC accumulation, indicating that the Sgo1–PP2A interaction is essential for the integrity of mitotic centromeres. We further provide evidence indicating that Sgo1 protects centromeric cohesin to create a binding site for the histone H3–associated protein kinase Haspin, which not only inhibits the cohesin release factor Wapl and thereby strengthens centromeric cohesion but also phosphorylates histone H3 at Thr-3 to position CPC at inner centromeres. Taken together, our findings reveal a positive feedback–based mechanism that ensures proper assembly of the functional inner centromere during mitosis. They further suggest a causal link between centromeric cohesion defects and chromosomal instability in cancer cells.

scholarly journals Liquid-liquid phase separation of the chromosomal passenger complex drives parallel bundling of midzone microtubules

2022 ◽  
Author(s):  
Ewa Niedzialkowska ◽  
Tan M Truong ◽  
Luke A Eldredge ◽  
Stefanie Redemann ◽  
Denis Chretien ◽  
...  
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Chromosome Segregation ◽  
Dynamic Structure ◽  
Liquid Phase Separation ◽  
Chromosomal Passenger Complex ◽  
Chromosomal Passenger ◽  
Spindle Midzone ◽  
Liquid Liquid Phase Separation

The spindle midzone is a dynamic structure that forms during anaphase, mediates chromosome segregation, and provides a signaling platform to position the cleavage furrow. The spindle midzone comprises two antiparallel bundles of microtubules (MTs) but the process of their formation is poorly understood. Here, we show that the Chromosomal Passenger Complex (CPC) undergoes liquid-liquid phase separation (LLPS) to generate parallel MT bundles in vitro when incubated with free tubulin and GTP. MT bundles emerge from CPC droplets with protruding minus-ends that then grow into long, tapered MT structures. During this growth, the CPC in condensates apparently reorganize to coat and bundle the resulting MT structures. CPC mutants attenuated for LLPS or MT binding prevented the generation of parallel MT bundles in vitro and reduced the number of MTs present at spindle midzones in HeLa cells. Our data uncovers a kinase-independent function of the CPC and provides models for how cells generate parallel-bundled MT structures that are important for the assembly of the mitotic spindle.

scholarly journals Chromatin rewiring mediates programmed evolvability via aneuploidy

2018 ◽  
Author(s):  
Cedric A. Brimacombe ◽  
Jordan E. Burke ◽  
Jahan-Yar Parsa ◽  
Jessica N. Witchley ◽  
Laura S. Burrack ◽  
...  
Keyword(s):  
Chromosome Segregation ◽  
Phosphorylation Site ◽  
Rapid Evolution ◽  
Histone H3 ◽  
Antifungal Drugs ◽  
High Fidelity ◽  
Histone H2a ◽  
Human Pathogen ◽  
Chromosome Missegregation ◽  
Mitosis And Meiosis

Eukaryotes have evolved elaborate mechanisms to ensure that chromosomes segregate with high fidelity during mitosis and meiosis1, and yet specific aneuploidies can be adaptive during environmental stress2,3. Here, we identify a chromatin-based system for inducible aneuploidy in a human pathogen. Candida albicans utilizes chromosome missegregation to acquire resistance to antifungal drugs4,5 and for ploidy reduction after mating6. We discovered that the ancestor of C. albicans and two related pathogens evolved a variant of histone H2A that lacks the conserved phosphorylation site for Bub1 kinase7, a key regulator of chromosome segregation1. Expression of this variant controls the rates of aneuploidy and antibiotic resistance in this species. Moreover, CENP-A/Cse4, the histone H3 that specifies centromeres, is depleted from tetraploid mating products and virtually eliminated from cells exposed to aneuploidy-promoting cues. Thus, changes in chromatin regulation can confer the capacity for rapid evolution in eukaryotes.

Phosphorylation of histone H3 by Haspin regulates chromosome alignment and segregation during mitosis in maize

2020 ◽  
Author(s):  
Yang Liu ◽  
Chunhui Wang ◽  
Handong Su ◽  
James A Birchler ◽  
Fangpu Han
Keyword(s):  
Chromosome Segregation ◽  
Histone H3 ◽  
Heterochromatin Protein 1 ◽  
Heterochromatin Protein ◽  
Factor B ◽  
Microtubule Attachment ◽  
Chromosome Alignment ◽  
Chromosomal Passenger ◽  
Mitosis And Meiosis

Abstract In human cells, Haspin-mediated histone H3 threonine 3 (H3T3) phosphorylation promotes centromeric localization of the chromosomal passenger complex, thereby ensuring proper kinetochore–microtubule attachment. Haspin also binds to PDS5 cohesin-associated factor B (Pds5B), antagonizing the Wings apart-like protein homolog (Wapl)–Pds5B interaction and thus preventing Wapl from releasing centromeric cohesion during mitosis. However, the role of Haspin in plant chromosome segregation is not well understood. Here, we show that in maize (Zea mays) mitotic cells, ZmHaspin localized to the centromere during metaphase and anaphase, whereas it localized to the telomeres during meiosis. These results suggest that ZmHaspin plays different roles during mitosis and meiosis. Knockout of ZmHaspin led to decreased H3T3 phosphorylation and histone H3 serine 10 phosphorylation, and defects in chromosome alignment and segregation in mitosis. These lines of evidence suggest that Haspin regulates chromosome segregation in plants via the mechanism described for humans, namely, H3T3 phosphorylation. Plant Haspin proteins lack the RTYGA and PxVxL motifs needed to bind Pds5B and heterochromatin protein 1, and no obvious cohesion defects were detected in ZmHaspin knockout plants. Taken together, these results highlight the conserved but slightly different roles of Haspin proteins in cell division in plants and in animals.

scholarly journals The Generation and Regulation of Tissue-Resident Tregs and Their Role in Autoimmune Diseases

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Shuang Wang ◽  
Xueyang Zou ◽  
Yi Zhang ◽  
Xiaoya Wang ◽  
Wei Yang ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
T Cells ◽  
Immune Responses ◽  
Autoimmune Diseases ◽  
Hot Spot ◽  
Exploratory Stage ◽  
And Function

Regulatory T cells (Tregs), as an important subset of T cells, play an important role in maintaining body homeostasis by regulating immune responses and preventing autoimmune diseases. In-depth research finds that Tregs have strong instability and plasticity, and according to their developmental origin, Tregs can be classified into thymic-derived Tregs (tTregs), endogenous-induced Tregs (pTregs), which are produced by antigen-stimulated T cells in the periphery in vivo, and induced Tregs (iTregs), which differentiate from naïve T cells in vitro. In recent years, studies have found that Tregs are divided into lymphatic and tissue-resident Tregs according to their location. Research on the generation and function of lymphoid Tregs has been more comprehensive and thorough, but the role of tissue Tregs is still in the exploratory stage, and it has become a research hot spot. In this review, we discuss the instability and plasticity of Tregs and the latest developments of tissue-resident Tregs in the field of biology, including adipose tissue, colon, skeletal muscle, and other Tregs that have been recently discovered as well as their production, regulation, and function in specific tissues and their role in the pathogenesis of autoimmune diseases.

scholarly journals Borealin–nucleosome interaction secures chromosome association of the chromosomal passenger complex

2019 ◽  
Vol 218 (12) ◽  
pp. 3912-3925 ◽  
Author(s):  
Maria A. Abad ◽  
Jan G. Ruppert ◽  
Lana Buzuk ◽  
Martin Wear ◽  
Juan Zou ◽  
...  
Keyword(s):  
Cell Division ◽  
Chromosome Segregation ◽  
Chromosome Association ◽  
Aurora B ◽  
Master Regulator ◽  
Multifaceted Approach ◽  
Chromosomal Passenger Complex ◽  
Chromosome Congression ◽  
Chromosomal Passenger ◽  
And Function

Chromosome association of the chromosomal passenger complex (CPC; consisting of Borealin, Survivin, INCENP, and the Aurora B kinase) is essential to achieve error-free chromosome segregation during cell division. Hence, understanding the mechanisms driving the chromosome association of the CPC is of paramount importance. Here using a multifaceted approach, we show that the CPC binds nucleosomes through a multivalent interaction predominantly involving Borealin. Strikingly, Survivin, previously suggested to target the CPC to centromeres, failed to bind nucleosomes on its own and requires Borealin and INCENP for its binding. Disrupting Borealin–nucleosome interactions excluded the CPC from chromosomes and caused chromosome congression defects. We also show that Borealin-mediated chromosome association of the CPC is critical for Haspin- and Bub1-mediated centromere enrichment of the CPC and works upstream of the latter. Our work thus establishes Borealin as a master regulator determining the chromosome association and function of the CPC.

Cyclic AMP-independent ATF family members interact with NF-kappa B and function in the activation of the E-selectin promoter in response to cytokines

1993 ◽  
Vol 13 (11) ◽  
pp. 7180-7190 ◽  
Author(s):  
W Kaszubska ◽  
R Hooft van Huijsduijnen ◽  
P Ghersa ◽  
A M DeRaemy-Schenk ◽  
B P Chen ◽  
...  
Keyword(s):  
Cyclic Amp ◽  
Consensus Sequence ◽  
Direct Interaction ◽  
Nf Kappa B ◽  
Independent Manner ◽  
Protein Protein Interaction ◽  
Responsive Element ◽  
And Function

We previously reported that NF-kappa B and a complex we referred to as NF-ELAM1 play a central role in cytokine-induced expression of the E-selectin gene. In this study we identify cyclic AMP (cAMP)-independent members of the ATF family binding specifically to the NF-ELAM1 promoter element. The NF-ELAM1 element (TGACATCA) differs by a single nucleotide substitution from the cAMP-responsive element consensus sequence. We demonstrate that this sequence operates in a cAMP-independent manner to induce transcription and thus define it as a non-cAMP-responsive element (NCRE). We show that ATFa is a component of the NF-ELAM1 complex and its overexpression activates the E-selectin promoter. In addition, ATFa, ATF2, and ATF3 interact directly with NF-kappa B in vitro, linking two unrelated families of transcription factors in a novel protein-protein interaction. Furthermore, we demonstrate that the ability of overexpressed NF-kappa B to transactivate the E-selectin promoter in vivo is dependent on the NF-ELAM1 complex. Our results suggest that a direct interaction between ATFs and NF-kappa B is, at least in part, the mechanism by which these factors specifically regulate E-selectin promoter activity.

scholarly journals EB1 enables spindle microtubules to regulate centromeric recruitment of Aurora B

2014 ◽  
Vol 204 (6) ◽  
pp. 947-963 ◽  
Author(s):  
Budhaditya Banerjee ◽  
Cortney A. Kestner ◽  
P. Todd Stukenberg
Keyword(s):  
Mitotic Chromosome ◽  
Histone H3 ◽  
Aurora B ◽  
Dependent Manner ◽  
Histone H2a ◽  
Aurora B Kinase ◽  
Chromosomal Passenger Complex ◽  
Checkpoint Signaling ◽  
Chromosomal Passenger ◽  
Spindle Microtubules

The Aurora B kinase coordinates kinetochore–microtubule attachments with spindle checkpoint signaling on each mitotic chromosome. We find that EB1, a microtubule plus end–tracking protein, is required to enrich Aurora B at inner centromeres in a microtubule-dependent manner. This regulates phosphorylation of both kinetochore and chromatin substrates. EB1 regulates the histone phosphorylation marks (histone H2A phospho-Thr120 and histone H3 phospho-Thr3) that localize Aurora B. The chromosomal passenger complex containing Aurora B can be found on a subset of spindle microtubules that exist near prometaphase kinetochores, known as preformed K-fibers (kinetochore fibers). Our data suggest that EB1 enables the spindle microtubules to regulate the phosphorylation of kinetochores through recruitment of the Aurora B kinase.

scholarly journals Malaria Pigment Hemozoin Impairs GM-CSF Receptor Expression and Function by 4-Hydroxynonenal

Antioxidants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1259
Author(s):  
Oleksii Skorokhod ◽  
Valentina Barrera ◽  
Giorgia Mandili ◽  
Federica Costanza ◽  
Elena Valente ◽  
...  
Keyword(s):  
Direct Interaction ◽  
Cell Types ◽  
Receptor Expression ◽  
Amino Acid Residues ◽  
Gm Csf ◽  
Malaria Pigment ◽  
Macrophage Colony Stimulating Factor ◽  
Macrophage Colony ◽  
And Function

Malarial pigment hemozoin (HZ) generates the lipoperoxidation product 4-hydroxynonenal (4-HNE), which is known to cause dysregulation of the immune response in malaria. The inhibition of granulocyte macrophage colony-stimulating factor (GM-CSF)-dependent differentiation of dendritic cells (DC) by HZ and 4-HNE was previously described in vitro, and the GM-CSF receptor (GM-CSF R) was hypothesised to be a primary target of 4-HNE in monocytes. In this study, we show the functional impact of HZ on GM-CSF R in monocytes and monocyte-derived DC by (i) impairing GM-CSF binding by 50 ± 9% and 65 ± 14%, respectively (n = 3 for both cell types); (ii) decreasing the expression of GM-CSF R functional subunit (CD116) on monocyte’s surface by 36 ± 11% (n = 6) and in cell lysate by 58 ± 16% (n = 3); and (iii) binding of 4-HNE to distinct amino acid residues on CD116. The data suggest that defective DC differentiation in malaria is caused by GM-CSF R dysregulation and GM-CSF R modification by lipoperoxidation product 4-HNE via direct interaction with its CD116 subunit.

Sign in / Sign up

Export Citation Format

Share Document