scholarly journals The Bifunctional FtsK Protein Mediates Chromosome Partitioning and Cell Division in Caulobacter

2006 ◽  
Vol 188 (4) ◽  
pp. 1497-1508 ◽  
Author(s):  
Sherry C. E. Wang ◽  
Lisandra West ◽  
Lucy Shapiro
Keyword(s):  
Cell Division ◽  
Chromosome Segregation ◽  
Caulobacter Crescentus ◽  
Topoisomerase Iv ◽  
Division Plane ◽  
Cellular Processes ◽  
Chromosome Partitioning ◽  
C Terminus ◽  
N Terminus ◽  
Necessary And Sufficient

ABSTRACT Bacterial chromosome partitioning and cell division are tightly connected cellular processes. We show here that the Caulobacter crescentus FtsK protein localizes to the division plane, where it mediates multiple functions involved in chromosome segregation and cytokinesis. The first 258 amino acids of the N terminus are necessary and sufficient for targeting the protein to the division plane. Furthermore, the FtsK N terminus is required to either assemble or maintain FtsZ rings at the division plane. The FtsK C terminus is essential in Caulobacter and is involved in maintaining accurate chromosome partitioning. In addition, the C-terminal region of FtsK is required for the localization of the topoisomerase IV ParC subunit to the replisome to facilitate chromosomal decatenation prior to cell division. These results suggest that the interdependence between chromosome partitioning and cell division in Caulobacter is mediated, in part, by the FtsK protein.

scholarly journals Activation of a signaling pathway by the physical translocation of a chromosome

2021 ◽  
Author(s):  
Mathilde Guzzo ◽  
Allen G. Sanderlin ◽  
Lennice K. Castro ◽  
Michael T. Laub
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Dna Replication ◽  
Signaling Pathway ◽  
Chromosome Segregation ◽  
Caulobacter Crescentus ◽  
Replication Initiation ◽  
Dna Replication Initiation ◽  
Cellular Processes ◽  
Initiation Of Dna Replication

AbstractIn every organism, the cell cycle requires the execution of multiple cellular processes in a strictly defined order. However, the mechanisms used to ensure such order remain poorly understood, particularly in bacteria. Here, we show that the activation of the essential CtrA signaling pathway that triggers cell division in Caulobacter crescentus is intrinsically coupled to the successful initiation of DNA replication via the physical translocation of a newly-replicated chromosome, powered by the ParABS system. We demonstrate that ParA accumulation at the new cell pole during chromosome segregation recruits ChpT, an intermediate component of the CtrA signaling pathway. ChpT is normally restricted from accessing the selective PopZ polar microdomain until the new chromosome and ParA arrive. Consequently, any disruption to DNA replication initiation prevents the recruitment of ChpT and, in turn, cell division. Collectively, our findings reveal how major cell-cycle events are coordinated in Caulobacter and, importantly, how the physical translocation of a chromosome triggers an essential signaling pathway.

scholarly journals RocS drives chromosome segregation and nucleoid occlusion in Streptococcus pneumoniae

2018 ◽  
Author(s):  
Chryslène Mercy ◽  
Jean-Pierre Lavergne ◽  
Jelle Slager ◽  
Adrien Ducret ◽  
Pierre Simon Garcia ◽  
...  
Keyword(s):  
Cell Division ◽  
Streptococcus Pneumoniae ◽  
Chromosome Segregation ◽  
Cellular Processes ◽  
Daughter Cells ◽  
Chromosome Partitioning ◽  
Replication Region ◽  
Membrane Bound ◽  
Opportunistic Human Pathogen ◽  
Immune Detection

AbstractSegregation of replicated chromosomes in bacteria is poorly understood outside some prominent model strains and even less is known about how it is coordinated with other cellular processes. Here we report that RocS is crucial for chromosome segregation in the opportunistic human pathogen Streptococcus pneumoniae. RocS is membrane-bound and interacts both with DNA and the chromosome partitioning protein ParB to properly segregate the origin of replication region to new daughter cells. In addition, we show that RocS interacts with the tyrosine-autokinase CpsD required for polysaccharide capsule biogenesis, which is crucial for S. pneumoniae’s ability to prevent host immune detection. Altering the RocS-CpsD interaction drastically hinders chromosome partitioning and cell division. Altogether, this work reveals that RocS is the cornerstone of an atypical nucleoid occlusion system ensuring proper cell division in coordination with the biogenesis of a protective capsular layer.

scholarly journals Role of the C Terminus of FtsK in Escherichia coli Chromosome Segregation

1998 ◽  
Vol 180 (23) ◽  
pp. 6424-6428 ◽  
Author(s):  
Xuan-Chuan Yu ◽  
Elizabeth K. Weihe ◽  
William Margolin
Keyword(s):  
Escherichia Coli ◽  
Cell Division ◽  
Chromosome Segregation ◽  
Null Mutation ◽  
Synthetic Lethal ◽  
Lethal Phenotype ◽  
Chromosome Partitioning ◽  
C Terminus

ABSTRACT FtsK is essential for Escherichia coli cell division. We report that cells lacking the C terminus of FtsK are defective in chromosome segregation as well as septation, often exhibiting asymmetrically positioned nucleoids and large anucleate regions. Combining the corresponding truncated ftsK gene with amukB null mutation resulted in a synthetic lethal phenotype. When the truncated ftsK was combined with aminCDE deletion, chains of minicells were generated, many of which contained DNA. These results suggest that the C terminus of FtsK has an important role in chromosome partitioning.

Simple topology: FtsK-directed recombination at the dif site

2013 ◽  
Vol 41 (2) ◽  
pp. 595-600 ◽  
Author(s):  
Ian Grainge
Keyword(s):  
Escherichia Coli ◽  
Cell Division ◽  
Chromosome Segregation ◽  
Motor Domain ◽  
Site Specific ◽  
Multifunctional Protein ◽  
Supercoiled Plasmid ◽  
C Terminus ◽  
Dna Translocase

FtsK is a multifunctional protein, which, in Escherichia coli, co-ordinates the essential functions of cell division, DNA unlinking and chromosome segregation. Its C-terminus is a DNA translocase, the fastest yet characterized, which acts as a septum-localized DNA pump. FtsK's C-terminus also interacts with the XerCD site-specific recombinases which act at the dif site, located in the terminus region. The motor domain of FtsK is an active translocase in vitro, and, when incubated with XerCD and a supercoiled plasmid containing two dif sites, recombination occurs to give unlinked circular products. Despite years of research the mechanism for this novel form of topological filter remains unknown.

Actopaxin is phosphorylated during mitosis and is a substrate for cyclin B1/cdc2 kinase

2002 ◽  
Vol 363 (2) ◽  
pp. 233-242 ◽  
Author(s):  
Michael CURTIS ◽  
Sotiris N. NIKOLOPOULOS ◽  
Christopher E. TURNER
Keyword(s):  
Cell Division ◽  
Focal Adhesions ◽  
Cyclin B1 ◽  
Actin Binding ◽  
Phosphorylation Sites ◽  
Cdc2 Kinase ◽  
C Terminus ◽  
N Terminus ◽  
Focal Adhesion Protein

Prior to cell division, normal adherent cells adopt a round morphology that is associated with a loss of actin stress fibres and disassembly of focal adhesions. In this study, we investigate the mitotic phosphorylation of the recently described paxillin and actin-binding focal-adhesion protein actopaxin [Nikolopoulos and Turner (2000) J. Cell Biol. 151, 1435–1448]. Actopaxin is comprised of an N-terminus containing six putative cdc2 phosphorylation sites and a C-terminus consisting of tandem calponin homology domains. Here we show that the N-terminus of actopaxin is phosphorylated by cyclin B1/cdc2 kinase in vitro and that this region of actopaxin precipitates cdc2 kinase activity from mitotic lysates. Actopaxin exhibits reduced electrophoretic mobility during mitosis that is dependent on phosphorylation within the first two consensus cdc2 phosphorylation sites. Finally, as cells progress from mitosis to G1 there is an adhesion-independent dephosphorylation of actopaxin, suggesting that actopaxin dephosphorylation precedes cell spreading and the reformation of focal adhesions. Taken together, these results suggest a role for cyclin B1/cdc2-dependent phosphorylation of actopaxin in regulating actin cytoskeleton reorganization during cell division.

scholarly journals ZapA tetramerization is required for midcell localization and ZapB interaction in Escherichia coli

2019 ◽  
Author(s):  
Nils Y. Meiresonne ◽  
Tanneke den Blaauwen
Keyword(s):  
Cell Division ◽  
Chromosome Segregation ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Bacterial Cell Division ◽  
Cellular Processes ◽  
Interaction Partners ◽  
Associated Proteins

AbstractBacterial cell division is guided by FtsZ treadmilling precisely at midcell. FtsZ itself is regulated by FtsZ associated proteins (Zaps) that couple it to different cellular processes. ZapA is known to enhance FtsZ bundling but also forms the synchronizing link with chromosome segregation through ZapB and matS bound MatP. ZapA exists as dimers and tetramers in the cell. Using the ZapAI83E mutant that only forms dimers, this paper investigates the effects of ZapA multimerization state on its interaction partners and cell division. By employing (fluorescence) microscopy and Förster Resonance Energy Transfer in vivo it is shown that; dimeric ZapA is unable to complement a zapA deletion strain and localizes diffusely through the cell but still interacts with FtsZ that is not part of the cell division machinery. Dimeric ZapA is unable to recruit ZapB, which localizes in its presence unipolarly in the cell. Interestingly, the localization profiles of the chromosome and unipolar ZapB anticorrelate. The work presented here confirms previously reported in vitro effects of ZapA multimerization in vivo and further places it in a broader context by revealing the strong implications for ZapB localization and ter linkage.

scholarly journals Dynamic nature of SecA and its associated proteins in Escherichia coli

2015 ◽  
Vol 6 ◽  
Author(s):  
Shun Adachi ◽  
Yasuhiro Murakawa ◽  
Sota Hiraga
Keyword(s):  
Escherichia Coli ◽  
Membrane Protein ◽  
Chromosome Segregation ◽  
Protein Translocation ◽  
Three Dimensional ◽  
Time Lapse ◽  
Topoisomerase Iv ◽  
Chromosome Partitioning ◽  
Functional Homolog ◽  
Associated Proteins

Mechanical properties such as physical constraint and pushing of chromosomes are thought to be important for chromosome segregation in Escherichia coli and it could be mediated by a hypothetical molecular “tether.” However, the actual tether that mediates these features is not known. We previously described that SecA (Secretory A) and Secretory Y (SecY), components of the membrane protein translocation machinery, and AcpP (Acyl carrier protein P) were involved in chromosome segregation and homeostasis of DNA topology. In the present work, we performed three-dimensional deconvolution of microscopic images and time-lapse experiments of these proteins together with MukB and DNA topoisomerases, and found that these proteins embraced the structures of tortuous nucleoids with condensed regions. Notably, SecA, SecY, and AcpP dynamically localized in cells, which was interdependent on each other requiring the ATPase activity of SecA. Our findings imply that the membrane protein translocation machinery plays a role in the maintenance of proper chromosome partitioning, possibly through “tethering” of MukB [a functional homolog of structural maintenance of chromosomes (SMC) proteins], DNA gyrase, DNA topoisomerase IV, and SeqA (Sequestration A).

scholarly journals Chromosome loss from par mutants of Pseudomonas putida depends on growth medium and phase of growth

Microbiology ◽  
2002 ◽  
Vol 148 (2) ◽  
pp. 537-548 ◽  
Author(s):  
Richard A Lewis ◽  
Colin R Bignell ◽  
Wei Zeng ◽  
Anthony C Jones ◽  
Christopher M Thomas
Keyword(s):  
Cell Division ◽  
Stationary Phase ◽  
Pseudomonas Putida ◽  
Chromosome Segregation ◽  
Copy Number ◽  
Minimal Medium ◽  
Exponential Phase ◽  
Chromosome Loss ◽  
Chromosome Partitioning ◽  
Mutant Phenotypes

The proteins encoded by chromosomal homologues of the parA and parB genes of many bacterial plasmids have been implicated in chromosome partitioning. Unlike their plasmid counterparts, mutant phenotypes produced by deleting these genes have so far been elusive or weakly expressed, except during sporulation. Here the properties of Pseudomonas putida strains with mutations in parA and parB are described. These mutants do not give rise to elevated levels of anucleate bacteria when grown in rich medium under standard conditions. However, in M9-minimal medium different parA and parB mutations gave between 5 and 10% anucleate cells during the transition from exponential phase to stationary phase. Comparison of the DNA content of bacteria at different stages of the growth curve, in batch culture in L-broth and in M9-minimal medium, suggests that the par genes are particularly important for chromosome partitioning when cell division reduces the chromosome copy number per cell from two to one. This transition occurs in P. putida during the entry into stationary phase in M9-minimal medium, but not in L-broth. It is proposed that the partition apparatus is important to ensure proper chromosome segregation primarily when the bacteria are undergoing cell division in the absence of ongoing DNA replication.

scholarly journals Chromosome segregation drives division site selection inStreptococcus pneumoniae

2016 ◽  
Author(s):  
Renske van Raaphorst ◽  
Morten Kjos ◽  
Jan-Willem Veening
Keyword(s):  
Cell Division ◽  
Chromosome Segregation ◽  
Site Selection ◽  
Bacterial Cell Division ◽  
Division Plane ◽  
Canonical Systems ◽  
Daughter Cells ◽  
Division Site ◽  
Additional Protein ◽  
Site Control

AbstractAccurate spatial and temporal positioning of the tubulin-like protein FtsZ is key for proper bacterial cell division.Streptococcus pneumoniae(pneumococcus) is an oval-shaped, symmetrically dividing human pathogen lacking the canonical systems for division site control (nucleoid occlusion and the Min-system). Recently, the early division protein MapZ was identified and implicated in pneumococcal division site selection. We show that MapZ is important for proper division plane selection; thus the question remains what drives pneumococcal division site selection. By mapping the cell cycle in detail, we show that directly after replication both chromosomal origin regions localize to the future cell division sites, prior to FtsZ. Perturbing the longitudinal chromosomal organization by mutating the condensin SMC, by CRISPR/Cas9-mediated chromosome cutting or by poisoning DNA decatenation resulted in mistiming of MapZ and FtsZ positioning and subsequent cell elongation. Together, we demonstrate an intimate relationship between DNA replication, chromosome segregation and division site selection in the pneumococcus, providing a simple way to ensure equally sized daughter cells without the necessity for additional protein factors.

scholarly journals Absence of the Polar Organizing Protein PopZ Results in Reduced and Asymmetric Cell Division in Agrobacterium tumefaciens

2017 ◽  
Vol 199 (17) ◽  
Author(s):  
Matthew Howell ◽  
Alena Aliashkevich ◽  
Anne K. Salisbury ◽  
Felipe Cava ◽  
Grant R. Bowman ◽  
...  
Keyword(s):  
Cell Division ◽  
Agrobacterium Tumefaciens ◽  
Chromosome Segregation ◽  
Caulobacter Crescentus ◽  
Length Distribution ◽  
Polar Growth ◽  
Atypical Cell ◽  
Content Type ◽  
Growth Pole ◽  
Animal Pathogens

ABSTRACT Agrobacterium tumefaciens is a rod-shaped bacterium that grows by polar insertion of new peptidoglycan during cell elongation. As the cell cycle progresses, peptidoglycan synthesis at the pole ceases prior to insertion of new peptidoglycan at midcell to enable cell division. The A. tumefaciens homolog of the Caulobacter crescentus polar organelle development protein PopZ has been identified as a growth pole marker and a candidate polar growth-promoting factor. Here, we characterize the function of PopZ in cell growth and division of A. tumefaciens. Consistent with previous observations, we observe that PopZ localizes specifically to the growth pole in wild-type cells. Despite the striking localization pattern of PopZ, we find the absence of the protein does not impair polar elongation or cause major changes in the peptidoglycan composition. Instead, we observe an atypical cell length distribution, including minicells, elongated cells, and cells with ectopic poles. Most minicells lack DNA, suggesting a defect in chromosome segregation. Furthermore, the canonical cell division proteins FtsZ and FtsA are misplaced, leading to asymmetric sites of cell constriction. Together, these data suggest that PopZ plays an important role in the regulation of chromosome segregation and cell division. IMPORTANCE A. tumefaciens is a bacterial plant pathogen and a natural genetic engineer. However, very little is known about the spatial and temporal regulation of cell wall biogenesis that leads to polar growth in this bacterium. Understanding the molecular basis of A. tumefaciens growth may allow for the development of innovations to prevent disease or to promote growth during biotechnology applications. Finally, since many closely related plant and animal pathogens exhibit polar growth, discoveries in A. tumefaciens may be broadly applicable for devising antimicrobial strategies.

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