scholarly journals Interphase centrosome organization by the PLP-Cnn scaffold is required for centrosome function

2015 ◽  
Vol 210 (1) ◽  
pp. 79-97 ◽  
Author(s):  
Dorothy A. Lerit ◽  
Holly A. Jordan ◽  
John S. Poulton ◽  
Carey J. Fagerstrom ◽  
Brian J. Galletta ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Drosophila Melanogaster ◽  
Cell Division ◽  
Structural Rearrangement ◽  
Functional Changes ◽  
Pericentriolar Material ◽  
Cycle Dependent ◽  
Embryonic Viability ◽  
Nuclear Spacing

Pericentriolar material (PCM) mediates the microtubule (MT) nucleation and anchoring activity of centrosomes. A scaffold organized by Centrosomin (Cnn) serves to ensure proper PCM architecture and functional changes in centrosome activity with each cell cycle. Here, we investigate the mechanisms that spatially restrict and temporally coordinate centrosome scaffold formation. Focusing on the mitotic-to-interphase transition in Drosophila melanogaster embryos, we show that the elaboration of the interphase Cnn scaffold defines a major structural rearrangement of the centrosome. We identify an unprecedented role for Pericentrin-like protein (PLP), which localizes to the tips of extended Cnn flares, to maintain robust interphase centrosome activity and promote the formation of interphase MT asters required for normal nuclear spacing, centrosome segregation, and compartmentalization of the syncytial embryo. Our data reveal that Cnn and PLP directly interact at two defined sites to coordinate the cell cycle–dependent rearrangement and scaffolding activity of the centrosome to permit normal centrosome organization, cell division, and embryonic viability.

The Xenopus protein kinase pEg2 associates with the centrosome in a cell cycle-dependent manner, binds to the spindle microtubules and is involved in bipolar mitotic spindle assembly

1998 ◽  
Vol 111 (5) ◽  
pp. 557-572 ◽  
Author(s):  
C. Roghi ◽  
R. Giet ◽  
R. Uzbekov ◽  
N. Morin ◽  
I. Chartrain ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Protein Kinase ◽  
Mitotic Spindle ◽  
Cultured Cells ◽  
Dependent Manner ◽  
Egg Extracts ◽  
Pericentriolar Material ◽  
Spindle Microtubules ◽  
Cycle Dependent

By differential screening of a Xenopus laevis egg cDNA library, we have isolated a 2,111 bp cDNA which corresponds to a maternal mRNA specifically deadenylated after fertilisation. This cDNA, called Eg2, encodes a 407 amino acid protein kinase. The pEg2 sequence shows significant identity with members of a new protein kinase sub-family which includes Aurora from Drosophila and Ipl1 (increase in ploidy-1) from budding yeast, enzymes involved in centrosome migration and chromosome segregation, respectively. A single 46 kDa polypeptide, which corresponds to the deduced molecular mass of pEg2, is immunodetected in Xenopus oocyte and egg extracts, as well as in lysates of Xenopus XL2 cultured cells. In XL2 cells, pEg2 is immunodetected only in S, G2 and M phases of the cell cycle, where it always localises to the centrosomal region of the cell. In addition, pEg2 ‘invades’ the microtubules at the poles of the mitotic spindle in metaphase and anaphase. Immunoelectron microscopy experiments show that pEg2 is located precisely around the pericentriolar material in prophase and on the spindle microtubules in anaphase. We also demonstrate that pEg2 binds directly to taxol stabilised microtubules in vitro. In addition, we show that the presence of microtubules during mitosis is not necessary for an association between pEg2 and the centrosome. Finally we show that a catalytically inactive pEg2 kinase stops the assembly of bipolar mitotic spindles in Xenopus egg extracts.

scholarly journals Effects of cell-cycle-dependent expression on random fluctuations in protein levels

2016 ◽  
Vol 3 (12) ◽  
pp. 160578 ◽  
Author(s):  
Mohammad Soltani ◽  
Abhyudai Singh
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Protein Levels ◽  
Stochastic Component ◽  
Stochastic Expression ◽  
A Cell ◽  
Intrinsic Stochasticity ◽  
Cycle Dependent ◽  
Random Fluctuations ◽  
Cell To Cell Variability

Expression of many genes varies as a cell transitions through different cell-cycle stages. How coupling between stochastic expression and cell cycle impacts cell-to-cell variability (noise) in the level of protein is not well understood. We analyse a model where a stable protein is synthesized in random bursts, and the frequency with which bursts occur varies within the cell cycle. Formulae quantifying the extent of fluctuations in the protein copy number are derived and decomposed into components arising from the cell cycle and stochastic processes. The latter stochastic component represents contributions from bursty expression and errors incurred during partitioning of molecules between daughter cells. These formulae reveal an interesting trade-off: cell-cycle dependencies that amplify the noise contribution from bursty expression also attenuate the contribution from partitioning errors. We investigate the existence of optimum strategies for coupling expression to the cell cycle that minimize the stochastic component. Intriguingly, results show that a zero production rate throughout the cell cycle, with expression only occurring just before cell division, minimizes noise from bursty expression for a fixed mean protein level. By contrast, the optimal strategy in the case of partitioning errors is to make the protein just after cell division. We provide examples of regulatory proteins that are expressed only towards the end of the cell cycle, and argue that such strategies enhance robustness of cell-cycle decisions to the intrinsic stochasticity of gene expression.

scholarly journals Abundances of transcripts, proteins, and metabolites in the cell cycle of budding yeast reveal coordinate control of lipid metabolism

2020 ◽  
Vol 31 (10) ◽  
pp. 1069-1084 ◽  
Author(s):  
Heidi M. Blank ◽  
Ophelia Papoulas ◽  
Nairita Maitra ◽  
Riddhiman Garge ◽  
Brian K. Kennedy ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Lipid Metabolism ◽  
Cell Division ◽  
Yeast Cell ◽  
Budding Yeast ◽  
Yeast Cells ◽  
Dynamic Changes ◽  
Coordinate Control ◽  
Cycle Dependent ◽  
Budding Yeast Cell Cycle

In several systems, including budding yeast, cell cycle-dependent changes in the transcriptome are well studied. In contrast, few studies queried the proteome during cell division. There is also little information about dynamic changes in metabolites and lipids in the cell cycle. Here, the authors present such information for dividing yeast cells.

scholarly journals Molecular cloning and cell-cycle-dependent expression of the acetyl-CoA synthetase gene in Tetrahymena cells

1999 ◽  
Vol 343 (2) ◽  
pp. 479-485 ◽  
Author(s):  
Shulin WANG ◽  
Shigeru NAKASHIMA ◽  
Osamu NUMATA ◽  
Kenta FUJIU ◽  
Yoshinori NOZAWA
Keyword(s):  
Heat Treatment ◽  
Cell Cycle ◽  
Cell Division ◽  
Amino Acid ◽  
Mrna Expression ◽  
Mrna Level ◽  
Cyclic Heat Treatment ◽  
Acetyl Coa ◽  
Synchronous Cell ◽  
Cycle Dependent

To identify transcriptionally regulated mediators associated with the cell cycle, we adopted the differential mRNA display technique for cell cultures of Tetrahymenapyriformis synchronized by cyclic heat treatment. One cDNA fragment that was expressed differently during synchronous cell division had a greatly decreased expression at 30 min after the end of heat treatment (EHT). Using this fragment as a probe, we isolated the full-length cDNA for T. pyriformis acetyl-CoA synthetase (TpAcs) which encodes a 651 amino acid polypeptide with a predicted molecular mass of 72.8 kDa. The deduced amino acid sequence of T. pyriformis ACS shows 42% sequence identity compared with that ofLysobacter sp. acetyl-CoA synthetase (ACS), an enzyme which catalyses the formation of acetyl-CoA from acetate via an acetyl-adenylate intermediate. The deduced sequence is also 41% and 40% identical compared with those of Pseudomonas putida and Coprinus cinereus ACS, respectively. The deduced sequence of T. pyriformis ACS also shares similar characteristics of the conserved motifs I and II in the ACS family. To further investigate the actions of the gene encoding this enzyme, mRNA expression was determined during the course of synchronized cell division in T. pyriformis. Northern blot results show that the mRNA level was dramatically decreased at 30 min after EHT prior to entering synchronous cell division (which occurs 75 min after EHT), suggesting that mRNA expression of the TpAcs was associated with the cell cycle and that the down-regulated expression of TpAcs at 30 min after EHT would be required for the initiation of the oncoming synchronous cell division in T. pyriformis.

Dynamics of the mitochondrial network during mitosis

2016 ◽  
Vol 44 (2) ◽  
pp. 510-516 ◽  
Author(s):  
Gil Kanfer ◽  
Benoît Kornmann
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Rho Gtpase ◽  
Cellular Structures ◽  
Mitochondrial Network ◽  
Mitochondrial Transport ◽  
Dynamic Events ◽  
Centromeric Protein ◽  
Protein F ◽  
Cycle Dependent

During mitosis, cells undergo massive deformation and reorganization, impacting on all cellular structures. Mitochondria, in particular, are highly dynamic organelles, which constantly undergo events of fission, fusion and cytoskeleton-based transport. This plasticity ensures the proper distribution of the metabolism, and the proper inheritance of functional organelles. During cell cycle, mitochondria undergo dramatic changes in distribution. In this review, we focus on the dynamic events that target mitochondria during mitosis. We describe how the cell-cycle-dependent microtubule-associated protein centromeric protein F (Cenp-F) is recruited to mitochondria by the mitochondrial Rho GTPase (Miro) to promote mitochondrial transport and re-distribution following cell division.

scholarly journals The Gene Expression and Enzyme Activity of Plant 3-Deoxy-D-Manno-2-Octulosonic Acid-8-Phosphate Synthase Are Preferentially Associated with Cell Division in a Cell Cycle-Dependent Manner

2003 ◽  
Vol 133 (1) ◽  
pp. 348-360 ◽  
Author(s):  
Frédéric Delmas ◽  
Johann Petit ◽  
Jérôme Joubès ◽  
Martial Séveno ◽  
Thomas Paccalet ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Cycle ◽  
Enzyme Activity ◽  
Cell Division ◽  
Dependent Manner ◽  
A Cell ◽  
Cycle Dependent ◽  
Phosphate Synthase

scholarly journals Cell cycle-dependent recruitment of FtsN to the divisome in Escherichia coli

2021 ◽  
Author(s):  
Jaana Mannik ◽  
Sebastien Pichoff ◽  
Joseph Lutkenhaus ◽  
Jaan Mannik
Keyword(s):  
Escherichia Coli ◽  
Cell Cycle ◽  
Cell Division ◽  
Cell Cycle Checkpoint ◽  
Second Stage ◽  
Cycle Checkpoint ◽  
Z Ring ◽  
Lag Period ◽  
Cycle Dependent ◽  
Rate Limiting

Cell division in Escherichia coli starts with the formation of an FtsZ protofilament network in the middle of the cell, the Z ring. However, only after a considerable lag period do the cells start to form a midcell constriction. The basis of this cell cycle checkpoint is yet unclear. The onset of constriction is dependent upon the arrival of so-called late divisome proteins, among which, FtsN is the last arriving essential one. The timing and dependency of FtsN arrival to the divisome, along with genetic evidence, suggests it triggers cell division. In this study, we used high throughput fluorescence microscopy to quantitatively determine the arrival of FtsN and the early divisome protein ZapA to midcell at a single-cell level during the cell cycle. Our data show that recruitment of FtsN coincides with the initiation of constriction within experimental uncertainties and that the relative fraction of ZapA/FtsZ reaches its highest value at this event. We also find that FtsN is recruited to midcell in two distinct temporal stages with septal peptidoglycan synthesis starting in the first stage and accelerating in the second stage, during which the amount of ZapA/FtsZ in the midcell decreases. In the presence of FtsA*, recruitment of FtsN becomes concurrent with the formation of the Z-ring, but constriction is still delayed indicating FtsN recruitment is not rate limiting, at least under these conditions. Finally, our data support the recently proposed idea that ZapA/FtsZ and FtsN are part of physically separate complexes in midcell throughout the whole septation process.

scholarly journals The coordinated localization of mRNA to centrosomes facilitates error-free mitosis

2020 ◽  
Author(s):  
Pearl V. Ryder ◽  
Junnan Fang ◽  
Dorothy A. Lerit
Keyword(s):  
Cell Cycle ◽  
Genome Stability ◽  
Fragile X ◽  
Protein Localization ◽  
Cell Types ◽  
Rna Granules ◽  
Mental Retardation Protein ◽  
Pericentriolar Material ◽  
Cycle Dependent ◽  
Post Transcriptional Regulation

AbstractCentrosomes are microtubule-organizing centers required for error-free mitosis and embryonic development. The microtubule-nucleating activity of centrosomes is conferred by the pericentriolar material (PCM), a composite of numerous proteins subject to cell cycle-dependent oscillations in levels and organization. In diverse cell types, mRNAs localize to centrosomes and may contribute to changes in PCM abundance. Here, we investigate the regulation of mRNA localization to centrosomes in the rapidly cycling Drosophila melanogaster embryo. We find that RNA localization to centrosomes is regulated during the cell cycle and developmentally. We identify a novel role for the fragile-X mental retardation protein (FMRP), which localizes to pericentrosomal RNA granules, in the post-transcriptional regulation of centrosomal RNA. Further, the mis-targeting of a model centrosomal mRNA, centrocortin (cen), is sufficient to alter cognate protein localization to centrosomes and impair spindle morphogenesis and genome stability.

scholarly journals The septin-associated kinase Gin4 recruits Gps1 to the site of cell division

2017 ◽  
Vol 28 (7) ◽  
pp. 883-889 ◽  
Author(s):  
Franz Meitinger ◽  
Gislene Pereira
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Cell Polarity ◽  
Rho Gtpases ◽  
G1 Phase ◽  
Division Site ◽  
Bud Neck ◽  
Unicellular Organisms ◽  
Cycle Dependent ◽  
Spatiotemporal Control

Cell cycle–dependent morphogenesis of unicellular organisms depends on the spatiotemporal control of cell polarity. Rho GTPases are the major players that guide cells through structural reorganizations such as cytokinesis (Rho1 dependent) and polarity establishment (Cdc42 dependent). In budding yeast, the protein Gps1 plays a pivotal role in both processes. Gps1 resides at the bud neck to maintain Rho1 localization and restrict Cdc42 activity during cytokinesis. Here we analyze how Gps1 is recruited to the bud neck during the cell cycle. We show that different regions of Gps1 and the septin-associated kinase Gin4 are involved in maintaining Gps1 at the bud neck from late G1 phase until midanaphase. From midanaphase, the targeting function of Gin4 is taken over by the bud neck–associated protein Nba1. Our data show that Gps1 is targeted to the cell division site in a biphasic manner, via Gin4 and Nba1, to control the spatiotemporal activation of Rho1 and inhibition of Cdc42.

scholarly journals Par6α Interacts with the Dynactin Subunit p150Glued and Is a Critical Regulator of Centrosomal Protein Recruitment

2010 ◽  
Vol 21 (19) ◽  
pp. 3376-3385 ◽  
Author(s):  
Andrew Kodani ◽  
Vinh Tonthat ◽  
Beibei Wu ◽  
Christine Sütterlin
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Protein Delivery ◽  
Protein Transport ◽  
Protein Composition ◽  
Microtubule Cytoskeleton ◽  
Centrosomal Protein ◽  
Cycle Dependent ◽  
Protein Recruitment

The centrosome contains proteins that control the organization of the microtubule cytoskeleton in interphase and mitosis. Its protein composition is tightly regulated through selective and cell cycle–dependent recruitment, retention, and removal of components. However, the mechanisms underlying protein delivery to the centrosome are not completely understood. We describe a novel function for the polarity protein Par6α in protein transport to the centrosome. We detected Par6α at the centrosome and centriolar satellites where it interacted with the centriolar satellite protein PCM-1 and the dynactin subunit p150Glued. Depletion of Par6α caused the mislocalization of p150Glued and centrosomal components that are critical for microtubule anchoring at the centrosome. As a consequence, there were severe alterations in the organization of the microtubule cytoskeleton in the absence of Par6α and cell division was blocked. We propose a model in which Par6α controls centrosome organization through its association with the dynactin subunit p150Glued.

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