scholarly journals Heat Shock Cognate 70 Functions as A Chaperone for the Stability of Kinetochore Protein CENP-N in Holocentric Insect Silkworms

2019 ◽  
Vol 20 (23) ◽  
pp. 5823
Author(s):  
Bingqian Li ◽  
Zhiqing Li ◽  
Chenchen Lu ◽  
Li Chang ◽  
Dongchao Zhao ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Heat Shock ◽  
Dna Sequences ◽  
Cellular Localization ◽  
Control Cell ◽  
Protein A ◽  
Holocentric Chromosomes ◽  
Centromere Protein ◽  
Heat Shock Cognate 70 ◽  
The Stability

The centromere, in which kinetochore proteins are assembled, plays an important role in the accurate congression and segregation of chromosomes during cell mitosis. Although the function of the centromere and kinetochore is conserved from monocentric to holocentric, the DNA sequences of the centromere and components of the kinetochore are varied among different species. Given the lack of core centromere protein A (CENP-A) and CENP-C in the lepidopteran silkworm Bombyx mori, which possesses holocentric chromosomes, here we investigated the role of CENP-N, another important member of the centromere protein family essential for kinetochore assembly. For the first time, cellular localization and RNA interference against CENP-N have confirmed its kinetochore function in silkworms. To gain further insights into the regulation of CENP-N in the centromere, we analyzed the affinity-purified complex of CENP-N by mass spectrometry and identified 142 interacting proteins. Among these factors, we found that the chaperone protein heat shock cognate 70 (HSC70) is able to regulate the stability of CENP-N by prohibiting ubiquitin–proteasome pathway, indicating that HSC70 could control cell cycle-regulated degradation of CENP-N at centromeres. Altogether, the present work will provide a novel clue to understand the regulatory mechanism for the kinetochore activity of CENP-N during the cell cycle.

scholarly journals Degradation of the Transcription Factor Gcn4 Requires the Kinase Pho85 and the SCFCDC4 Ubiquitin–Ligase Complex

2000 ◽  
Vol 11 (3) ◽  
pp. 915-927 ◽  
Author(s):  
Ariella Meimoun ◽  
Tsvi Holtzman ◽  
Ziva Weissman ◽  
Helen J. McBride ◽  
David J. Stillman ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Transcription Factor ◽  
Ubiquitin Ligase ◽  
Protein A ◽  
Purine Biosynthesis ◽  
Cell Cycle Regulators ◽  
Rich Medium ◽  
Ubiquitin Ligase Complex ◽  
Ubiquitin Conjugating Enzyme ◽  
The Stability

Gcn4, a yeast transcriptional activator that promotes the expression of amino acid and purine biosynthesis genes, is rapidly degraded in rich medium. Here we report that SCFCDC4, a recently characterized protein complex that acts in conjunction with the ubiquitin-conjugating enzyme Cdc34 to degrade cell cycle regulators, is also necessary for the degradation of the transcription factor Gcn4. Degradation of Gcn4 occurs throughout the cell cycle, whereas degradation of the known cell cycle substrates of Cdc34/SCFCDC4 is cell cycle regulated. Gcn4 ubiquitination and degradation are regulated by starvation for amino acids, whereas the degradation of the cell cycle substrates of Cdc34/SCFCDC4 is unaffected by starvation. We further show that unlike the cell cycle substrates of Cdc34/SCFCDC4, which require phosphorylation by the kinase Cdc28, Gcn4 degradation requires the kinase Pho85. We identify the critical target site of Pho85 on Gcn4; a mutation of this site stabilizes the protein. A specific Pho85-Pcl complex that is able to phosphorylate Gcn4 on that site is inactive under conditions under which Gcn4 is stable. Thus, Cdc34/SCFCDC4 activity is constitutive, and regulation of the stability of its various substrates occurs at the level of their phosphorylation.

scholarly journals Assembly in G1 phase and long-term stability are unique intrinsic features of CENP-A nucleosomes

2013 ◽  
Vol 24 (7) ◽  
pp. 923-932 ◽  
Author(s):  
Dani L. Bodor ◽  
Luis P. Valente ◽  
João F. Mata ◽  
Ben E. Black ◽  
Lars E. T. Jansen
Keyword(s):  
Cell Cycle ◽  
Dna Sequences ◽  
Protein A ◽  
G1 Phase ◽  
Term Stability ◽  
Nucleosome Core ◽  
Long Term Stability ◽  
Centromere Position ◽  
Centromere Protein A

Centromeres are the site of kinetochore formation during mitosis. Centromere protein A (CENP-A), the centromere-specific histone H3 variant, is essential for the epigenetic maintenance of centromere position. Previously we showed that newly synthesized CENP-A is targeted to centromeres exclusively during early G1 phase and is subsequently maintained across mitotic divisions. Using SNAP-based fluorescent pulse labeling, we now demonstrate that cell cycle–restricted chromatin assembly at centromeres is unique to CENP-A nucleosomes and does not involve assembly of other H3 variants. Strikingly, stable retention is restricted to the CENP-A/H4 core of the nucleosome, which we find to outlast general chromatin across several cell divisions. We further show that cell cycle timing of CENP-A assembly is independent of centromeric DNA sequences and instead is mediated by the CENP-A targeting domain. Unexpectedly, this domain also induces stable transmission of centromeric nucleosomes, independent of the CENP-A deposition factor HJURP. This demonstrates that intrinsic properties of the CENP-A protein direct its cell cycle–restricted assembly and induces quantitative mitotic transmission of the CENP-A/H4 nucleosome core, ensuring long-term stability and epigenetic maintenance of centromere position.

scholarly journals Functional Complementation of Human Centromere Protein A (CENP-A) by Cse4p from Saccharomyces cerevisiae

2004 ◽  
Vol 24 (15) ◽  
pp. 6620-6630 ◽  
Author(s):  
Gerhard Wieland ◽  
Sandra Orthaus ◽  
Sabine Ohndorf ◽  
Stephan Diekmann ◽  
Peter Hemmerich
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Cell Cycle Arrest ◽  
Budding Yeast ◽  
Protein A ◽  
Human Cells ◽  
Cycle Arrest ◽  
Centromere Protein ◽  
Centromere Protein A

ABSTRACT We have employed a novel in vivo approach to study the structure and function of the eukaryotic kinetochore multiprotein complex. RNA interference (RNAi) was used to block the synthesis of centromere protein A (CENP-A) and Clip-170 in human cells. By coexpression, homologous kinetochore proteins from Saccharomyces cerevisiae were then tested for the ability to complement the RNAi-induced phenotypes. Cse4p, the budding yeast CENP-A homolog, was specifically incorporated into kinetochore nucleosomes and was able to complement RNAi-induced cell cycle arrest in CENP-A-depleted human cells. Thus, Cse4p can structurally and functionally substitute for CENP-A, strongly suggesting that the basic features of centromeric chromatin are conserved between yeast and mammals. Bik1p, the budding yeast homolog of human CLIP-170, also specifically localized to kinetochores during mitosis, but Bik1p did not rescue CLIP-170 depletion-induced cell cycle arrest. Generally, the newly developed in vivo complementation assay provides a powerful new tool for studying the function and evolutionary conservation of multiprotein complexes from yeast to humans.

scholarly journals The CIRCE Element and Its Putative Repressor Control Cell Cycle Expression of the Caulobacter crescentus groESLOperon

1998 ◽  
Vol 180 (7) ◽  
pp. 1632-1641 ◽  
Author(s):  
Regina Lúcia Baldini ◽  
Marcelo Avedissian ◽  
Suely Lopes Gomes
Keyword(s):  
Cell Cycle ◽  
Heat Shock ◽  
Caulobacter Crescentus ◽  
Cell Cycle Control ◽  
Control Cell ◽  
Regulatory Region ◽  
Normal Growth ◽  
Site Directed Mutagenesis ◽  
Minor Effect ◽  
Negative Role

ABSTRACT The groESL operon is under complex regulation inCaulobacter crescentus. In addition to strong induction after exposure to heat shock, under physiological growth conditions, its expression is subject to cell cycle control. Transcription and translation of the groE genes occur primarily in predivisional cells, with very low levels of expression in stalked cells. The regulatory region of groESL contains both a ς32-like promoter and a CIRCE element. Overexpression ofC. crescentus ς32 gives rise to higher levels of GroEL and increased levels of the groESL transcript coming from the ς32-like promoter. Site-directed mutagenesis in CIRCE has indicated a negative role for thiscis-acting element in the expression of groESLonly at normal growth temperatures, with a minor effect on heat shock induction. Furthermore, groESL-lacZ transcription fusions carrying mutations in CIRCE are no longer cell cycle regulated. Analysis of an hrcA null strain, carrying a disruption in the gene encoding the putative repressor that binds to the CIRCE element, shows constitutive synthesis of GroEL throughout theCaulobacter cell cycle. These results indicate a negative role for the hrcA gene product and the CIRCE element in the temporal control of the groESL operon.

scholarly journals Heat shock cognate 70 protein secretion as a new growth arrest signal for cancer cells

Oncogene ◽  
2009 ◽  
Vol 29 (1) ◽  
pp. 117-127 ◽  
Author(s):  
P Nirdé ◽  
D Derocq ◽  
M Maynadier ◽  
M Chambon ◽  
I Basile ◽  
...  
Keyword(s):  
Heat Shock ◽  
Cancer Cells ◽  
Protein Secretion ◽  
Growth Arrest ◽  
Heat Shock Cognate 70

scholarly journals Positive Feedback Between PU.1 and the Cell Cycle Controls Myeloid Differentiation

Science ◽  
2013 ◽  
Vol 341 (6146) ◽  
pp. 670-673 ◽  
Author(s):  
Hao Yuan Kueh ◽  
Ameya Champhekar ◽  
Stephen L. Nutt ◽  
Michael B. Elowitz ◽  
Ellen V. Rothenberg
Keyword(s):  
Cell Cycle ◽  
Cell Fate ◽  
Positive Feedback ◽  
Regulatory Gene ◽  
Control Cell ◽  
Stem Cell Differentiation ◽  
Myeloid Differentiation ◽  
Cycle Duration ◽  
Gene Circuits ◽  
Cell Cycles

Regulatory gene circuits with positive-feedback loops control stem cell differentiation, but several mechanisms can contribute to positive feedback. Here, we dissect feedback mechanisms through which the transcription factor PU.1 controls lymphoid and myeloid differentiation. Quantitative live-cell imaging revealed that developing B cells decrease PU.1 levels by reducing PU.1 transcription, whereas developing macrophages increase PU.1 levels by lengthening their cell cycles, which causes stable PU.1 accumulation. Exogenous PU.1 expression in progenitors increases endogenous PU.1 levels by inducing cell cycle lengthening, implying positive feedback between a regulatory factor and the cell cycle. Mathematical modeling showed that this cell cycle–coupled feedback architecture effectively stabilizes a slow-dividing differentiated state. These results show that cell cycle duration functions as an integral part of a positive autoregulatory circuit to control cell fate.

scholarly journals RAE-1 ligands for the NKG2D receptor are regulated by E2F transcription factors, which control cell cycle entry

2012 ◽  
Vol 209 (13) ◽  
pp. 2409-2422 ◽  
Author(s):  
Heiyoun Jung ◽  
Benjamin Hsiung ◽  
Kathleen Pestal ◽  
Emily Procyk ◽  
David H. Raulet
Keyword(s):  
Cell Cycle ◽  
Transcription Factors ◽  
Stress Responses ◽  
Transcriptional Activation ◽  
Posttranscriptional Regulation ◽  
Cellular Proliferation ◽  
Control Cell ◽  
T Cell Subsets ◽  
Cell Cycle Entry

The NKG2D stimulatory receptor expressed by natural killer cells and T cell subsets recognizes cell surface ligands that are induced on transformed and infected cells and facilitate immune rejection of tumor cells. We demonstrate that expression of retinoic acid early inducible gene 1 (RAE-1) family NKG2D ligands in cancer cell lines and proliferating normal cells is coupled directly to cell cycle regulation. Raet1 genes are directly transcriptionally activated by E2F family transcription factors, which play a central role in regulating cell cycle entry. Induction of RAE-1 occurred in primary cell cultures, embryonic brain cells in vivo, and cells in healing skin wounds and, accordingly, wound healing was delayed in mice lacking NKG2D. Transcriptional activation by E2Fs is likely coordinated with posttranscriptional regulation by other stress responses. These findings suggest that cellular proliferation, as occurs in cancer cells but also other pathological conditions, is a key signal tied to immune reactions mediated by NKG2D-bearing lymphocytes.

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