scholarly journals Novel Divisome-Associated Protein Spatially Coupling the Z-Ring with the Chromosomal Replication Terminus in Caulobacter crescentus

mBio ◽  
2020 ◽  
Vol 11 (2) ◽  
Author(s):  
Shogo Ozaki ◽  
Urs Jenal ◽  
Tsutomu Katayama
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Caulobacter Crescentus ◽  
Enteric Bacteria ◽  
Chromosome Replication ◽  
Chromosomal Replication ◽  
Content Type ◽  
Physical Linkage ◽  
Z Ring ◽  
Replication Terminus

ABSTRACT Cell division requires proper spatial coordination with the chromosome, which undergoes dynamic changes during chromosome replication and segregation. FtsZ is a bacterial cytoskeletal protein that assembles into the Z-ring, providing a platform to build the cell division apparatus. In the model bacterium Caulobacter crescentus, the cellular localization of the Z-ring is controlled during the cell cycle in a chromosome replication-coupled manner. Although dynamic localization of the Z-ring at midcell is driven primarily by the replication origin-associated FtsZ inhibitor MipZ, the mechanism ensuring accurate positioning of the Z-ring remains unclear. In this study, we showed that the Z-ring colocalizes with the replication terminus region, located opposite the origin, throughout most of the C. crescentus cell cycle. Spatial organization of the two is mediated by ZapT, a previously uncharacterized protein that interacts with the terminus region and associates with ZapA and ZauP, both of which are part of the incipient division apparatus. While the Z-ring and the terminus region coincided with the presence of ZapT, colocalization of the two was perturbed in cells lacking zapT, which is accompanied by delayed midcellular positioning of the Z-ring. Moreover, cells overexpressing ZapT showed compromised positioning of the Z-ring and MipZ. These findings underscore the important role of ZapT in controlling cell division processes. We propose that ZapT acts as a molecular bridge that physically links the terminus region to the Z-ring, thereby ensuring accurate site selection for the Z-ring. Because ZapT is conserved in proteobacteria, these findings may define a general mechanism coordinating cell division with chromosome organization. IMPORTANCE Growing bacteria require careful tuning of cell division processes with dynamic organization of replicating chromosomes. In enteric bacteria, ZapA associates with the cytoskeletal Z-ring and establishes a physical linkage to the chromosomal replication terminus through its interaction with ZapB-MatP-DNA complexes. However, because ZapB and MatP are found only in enteric bacteria, it remains unclear how the Z-ring and the terminus are coordinated in the vast majority of bacteria. Here, we provide evidence that a novel conserved protein, termed ZapT, mediates colocalization of the Z-ring with the terminus in Caulobacter crescentus, a model organism that is phylogenetically distant from enteric bacteria. Given that ZapT facilitates cell division processes in C. crescentus, this study highlights the universal importance of the physical linkage between the Z-ring and the terminus in maintaining cell integrity.

scholarly journals Z-Ring-Associated Proteins Regulate Clustering of the Replication Terminus-Binding Protein ZapT in Caulobacter crescentus

mBio ◽  
2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Shogo Ozaki ◽  
Yasutaka Wakasugi ◽  
Tsutomu Katayama
Keyword(s):  
Caulobacter Crescentus ◽  
Binding Protein ◽  
Specific Interaction ◽  
Common Mechanism ◽  
Dna Complexes ◽  
Content Type ◽  
Physical Linkage ◽  
Associated Proteins ◽  
Z Ring ◽  
Replication Terminus

ABSTRACT Regulated organization of the chromosome is essential for faithful propagation of genetic information. In the model bacterium Caulobacter crescentus, the replication terminus of the chromosome is spatially arranged in close proximity to the cytokinetic Z-ring during the cell cycle. Although the Z-ring-associated proteins ZapA and ZauP interact with the terminus recognition protein ZapT, the molecular functions of the complex that physically links the terminus and the Z-ring remain obscure. In this study, we found that the physical linkage helps to organize the terminus DNA into a clustered structure. Neither ZapA nor ZauP was required for ZapT binding to the terminus DNA, but clustering of the ZapT-DNA complexes over the Z-ring was severely compromised in cells lacking ZapA or ZauP. Biochemical characterization revealed that ZapT, ZauP, and ZapA interacted directly to form a highly ordered ternary complex. Moreover, multiple ZapT molecules were sequestered by each ZauP oligomer. Investigation of the functional structure of ZapT revealed that the C terminus of ZapT specifically interacted with ZauP and was essential for timely positioning of the Z-ring in vivo. Based on these findings, we propose that ZauP-dependent oligomerization of ZapT-DNA complexes plays a distinct role in organizing the replication terminus and the Z-ring. The C termini of ZapT homologs share similar chemical properties, implying a common mechanism for the physical linkage between the terminus and the Z-ring in bacteria. IMPORTANCE Rapidly growing bacteria experience dynamic changes in chromosome architecture during chromosome replication and segregation, reflecting the importance of mechanisms that organize the chromosome globally and locally within a cell to maintain faithful transmission of genetic material across generations. During cell division in the model bacterium Caulobacter crescentus, the replication terminus of the chromosome is physically linked to the cytokinetic Z-ring at midcell. However, the functions of this physical linkage are not fully understood. We adopted biochemical and cell-biological techniques to characterize the linkage, including the terminus-binding protein ZapT and the Z-ring-associated protein ZauP. We obtained evidence that the Z-ring organizes the chromosome terminus into a compact structure at midcell via specific interaction between ZapT and ZauP oligomers. Because these proteins are conserved in diverse Gram-negative bacteria, our findings highlight a novel and conserved role for the linker complex in regulated organization of the chromosome terminus.

scholarly journals The Chaperonin GroESL Facilitates Caulobacter crescentus Cell Division by Supporting the Functions of the Z-Ring Regulators FtsA and FzlA

mBio ◽  
2021 ◽  
Vol 12 (3) ◽  
Author(s):  
Kristen Schroeder ◽  
Kristina Heinrich ◽  
Ines Neuwirth ◽  
Kristina Jonas
Keyword(s):  
Cell Cycle ◽  
Cell Wall ◽  
Cell Division ◽  
Bacterial Cell ◽  
Antimicrobial Agents ◽  
Caulobacter Crescentus ◽  
Content Type ◽  
Growing Cell ◽  
Z Ring ◽  
Bacterial Cell Cycle

ABSTRACT The highly conserved chaperonin GroESL performs a crucial role in protein folding; however, the essential cellular pathways that rely on this chaperone are underexplored. Loss of GroESL leads to severe septation defects in diverse bacteria, suggesting the folding function of GroESL may be integrated with the bacterial cell cycle at the point of cell division. Here, we describe new connections between GroESL and the bacterial cell cycle using the model organism Caulobacter crescentus. Using a proteomics approach, we identify candidate GroESL client proteins that become insoluble or are degraded specifically when GroESL folding is insufficient, revealing several essential proteins that participate in cell division and peptidoglycan biosynthesis. We demonstrate that other cell cycle events, such as DNA replication and chromosome segregation, are able to continue when GroESL folding is insufficient. We further find that deficiency of two FtsZ-interacting proteins, the bacterial actin homologue FtsA and the constriction regulator FzlA, mediate the GroESL-dependent block in cell division. Our data show that sufficient GroESL is required to maintain normal dynamics of the FtsZ scaffold and divisome functionality in C. crescentus. In addition to supporting divisome function, we show that GroESL is required to maintain the flow of peptidoglycan precursors into the growing cell wall. Linking a chaperone to cell division may be a conserved way to coordinate environmental and internal cues that signal when it is safe to divide. IMPORTANCE All organisms depend on mechanisms that protect proteins from misfolding and aggregation. GroESL is a highly conserved molecular chaperone that functions to prevent protein aggregation in organisms ranging from bacteria to humans. Despite detailed biochemical understanding of GroESL function, the in vivo pathways that strictly depend on this chaperone remain poorly defined in most species. This study provides new insights into how GroESL is linked to the bacterial cell division machinery, a crucial target of current and future antimicrobial agents. We identify a functional interaction between GroESL and the cell division proteins FzlA and FtsA, which modulate Z-ring function. FtsA is a conserved bacterial actin homologue, suggesting that as in eukaryotes, some bacteria exhibit a connection between cytoskeletal actin proteins and chaperonins. Our work further defines how GroESL is integrated with cell wall synthesis and illustrates how highly conserved folding machines ensure the functioning of fundamental cellular processes during stress.

scholarly journals Loss of PodJ in Agrobacterium tumefaciens Leads to Ectopic Polar Growth, Branching, and Reduced Cell Division

2016 ◽  
Vol 198 (13) ◽  
pp. 1883-1891 ◽  
Author(s):  
James C. Anderson-Furgeson ◽  
John R. Zupan ◽  
Romain Grangeon ◽  
Patricia C. Zambryski
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Agrobacterium Tumefaciens ◽  
Cell Envelope ◽  
Critical Factor ◽  
Polar Growth ◽  
Content Type ◽  
Growth Pole ◽  
Envelope Material ◽  
Z Ring

ABSTRACTAgrobacterium tumefaciensis a rod-shaped Gram-negative bacterium that elongates by unipolar addition of new cell envelope material. Approaching cell division, the growth pole transitions to a nongrowing old pole, and the division site creates new growth poles in sibling cells. TheA. tumefacienshomolog of theCaulobacter crescentuspolar organizing protein PopZ localizes specifically to growth poles. In contrast, theA. tumefacienshomolog of theC. crescentuspolar organelle development protein PodJ localizes to the old pole early in the cell cycle and accumulates at the growth pole as the cell cycle proceeds. FtsA and FtsZ also localize to the growth pole for most of the cell cycle prior to Z-ring formation. To further characterize the function of polar localizing proteins, we created a deletion ofA. tumefacienspodJ(podJAt). ΔpodJAtcells display ectopic growth poles (branching), growth poles that fail to transition to an old pole, and elongated cells that fail to divide. In ΔpodJAtcells,A. tumefaciensPopZ-green fluorescent protein (PopZAt-GFP) persists at nontransitioning growth poles postdivision and also localizes to ectopic growth poles, as expected for a growth-pole-specific factor. Even though GFP-PodJAtdoes not localize to the midcell in the wild type, deletion ofpodJAtimpacts localization, stability, and function of Z-rings as assayed by localization of FtsA-GFP and FtsZ-GFP. Z-ring defects are further evidenced by minicell production. Together, these data indicate that PodJAtis a critical factor for polar growth and that ΔpodJAtcells display a cell division phenotype, likely because the growth pole cannot transition to an old pole.IMPORTANCEHow rod-shaped prokaryotes develop and maintain shape is complicated by the fact that at least two distinct species-specific growth modes exist: uniform sidewall insertion of cell envelope material, characterized in model organisms such asEscherichia coli, and unipolar growth, which occurs in several alphaproteobacteria, includingAgrobacterium tumefaciens. Essential components for unipolar growth are largely uncharacterized, and the mechanism constraining growth to one pole of a wild-type cell is unknown. Here, we report that the deletion of a polar development gene,podJAt, results in cells exhibiting ectopic polar growth, including multiple growth poles and aberrant localization of cell division and polar growth-associated proteins. These data suggest that PodJAtis a critical factor in normal polar growth and impacts cell division inA. tumefaciens.

scholarly journals Genomic Adaptations to the Loss of a Conserved Bacterial DNA Methyltransferase

mBio ◽  
2015 ◽  
Vol 6 (4) ◽  
Author(s):  
Diego Gonzalez ◽  
Justine Collier
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Experimental Evolution ◽  
Dna Methyltransferase ◽  
Metabolic Regulation ◽  
Caulobacter Crescentus ◽  
Point Mutations ◽  
Rich Medium ◽  
Content Type ◽  
Evolution Approach

ABSTRACTCcrM is an orphan DNA methyltransferase nearly universally conserved in a vast group ofAlphaproteobacteria.InCaulobacter crescentus, it controls the expression of key genes involved in the regulation of the cell cycle and cell division. Here, we demonstrate, using an experimental evolution approach, thatC. crescentuscan significantly compensate, through easily accessible genetic changes like point mutations, the severe loss in fitness due to the absence of CcrM, quickly improving its growth rate and cell morphology in rich medium. By analyzing the compensatory mutations genome-wide in 12 clones sampled from independent ΔccrMpopulations evolved for ~300 generations, we demonstrated that each of the twelve clones carried at least one mutation that potentially stimulatedftsZexpression, suggesting that the low intracellular levels of FtsZ are the major burden of ΔccrMmutants. In addition, we demonstrate that the phosphoenolpyruvate-carbohydrate phosphotransfer system (PTS) actually modulatesftsZandmipZtranscription, uncovering a previously unsuspected link between metabolic regulation and cell division inAlphaproteobacteria. We present evidence that point mutations found in genes encoding proteins of the PTS provide the strongest fitness advantage to ΔccrMcells cultivated in rich medium despite being disadvantageous in minimal medium. This environmental sign epistasis might prevent such mutations from getting fixed under changing natural conditions, adding a plausible explanation for the broad conservation of CcrM.IMPORTANCEIn bacteria, DNA methylation has a variety of functions, including the control of DNA replication and/or gene expression. The cell cycle-regulated DNA methyltransferase CcrM modulates the transcription of many genes and is critical for fitness inCaulobacter crescentus. Here, we used an original experimental evolution approach to determine which of its many targets make CcrM so important physiologically. We show that populations lacking CcrM evolve quickly, accumulating an excess of mutations affecting, directly or indirectly, the expression of theftsZcell division gene. This finding suggests that the most critical function of CcrM inC. crescentusis to promote cell division by enhancing FtsZ intracellular levels. During this work, we also discovered an unexpected link between metabolic regulation and cell division that might extend to otherAlphaproteobacteria.

scholarly journals Chromosome Dynamics in Bacteria: Triggering Replication at the Opposite Location and Segregation in the Opposite Direction

mBio ◽  
2019 ◽  
Vol 10 (4) ◽  
Author(s):  
Ady B. Meléndez ◽  
Inoka P. Menikpurage ◽  
Paola E. Mera
Keyword(s):  
Cell Cycle ◽  
Chromosome Segregation ◽  
Opposite Direction ◽  
Caulobacter Crescentus ◽  
Chromosome Replication ◽  
Opposite Orientation ◽  
Circular Chromosome ◽  
Content Type ◽  
Cell Pole ◽  
Protein Gradients

ABSTRACT Maintaining the integrity of the genome is essential to cell survival. In the bacterium Caulobacter crescentus, the single circular chromosome exhibits a specific orientation in the cell, with the replication origin (ori) residing at the pole of the cell bearing a stalk. Upon initiation of replication, the duplicated centromere-like region parS and ori move rapidly to the opposite pole where parS is captured by a microdomain hosting a unique set of proteins that contribute to the identity of progeny cells. Many questions remain as to how this organization is maintained. In this study, we constructed strains of Caulobacter in which ori and the parS centromere can be induced to move to the opposite cell pole in the absence of chromosome replication, allowing us to ask whether once these chromosomal foci were positioned at the wrong pole, replication initiation and chromosome segregation can proceed in the opposite orientation. Our data reveal that DnaA can initiate replication and ParA can orchestrate segregation from either cell pole. The cell reconstructs the organization of its ParA gradient in the opposite orientation to segregate one replicated centromere from the new pole toward the stalked pole (i.e., opposite direction), while displaying no detectable viability defects. Thus, the unique polar microdomains exhibit remarkable flexibility in serving as a platform for directional chromosome segregation along the long axis of the cell. IMPORTANCE Bacteria can accomplish surprising levels of organization in the absence of membrane organelles by constructing subcellular asymmetric protein gradients. These gradients are composed of regulators that can either trigger or inhibit cell cycle events from distinct cell poles. In Caulobacter crescentus, the onset of chromosome replication and segregation from the stalked pole are regulated by asymmetric protein gradients. We show that the activators of chromosome replication and segregation are not restricted to the stalked pole and that their organization and directionality can be flipped in orientation. Our results also indicate that the subcellular location of key chromosomal loci play important roles in the establishment of the asymmetric organization of cell cycle regulators.

scholarly journals Coordination between Chromosome Replication, Segregation, and Cell Division in Caulobacter crescentus

2006 ◽  
Vol 188 (6) ◽  
pp. 2244-2253 ◽  
Author(s):  
Rasmus B. Jensen
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Dna Replication ◽  
Cytoplasmic Membrane ◽  
Caulobacter Crescentus ◽  
Chromosome Replication ◽  
Short Delay ◽  
Swarmer Cell ◽  
Initiation Of Dna Replication ◽  
Cell Transition

ABSTRACT Progression through the Caulobacter crescentus cell cycle is coupled to a cellular differentiation program. The swarmer cell is replicationally quiescent, and DNA replication initiates at the swarmer-to-stalked cell transition. There is a very short delay between initiation of DNA replication and movement of one of the newly replicated origins to the opposite pole of the cell, indicating the absence of cohesion between the newly replicated origin-proximal parts of the Caulobacter chromosome. The terminus region of the chromosome becomes located at the invaginating septum in predivisional cells, and the completely replicated terminus regions stay associated with each other after chromosome replication is completed, disassociating very late in the cell cycle shortly before the final cell division event. Invagination of the cytoplasmic membrane occurs earlier than separation of the replicated terminus regions and formation of separate nucleoids, which results in trapping of a chromosome on either side of the cell division septum, indicating that there is not a nucleoid exclusion phenotype.

scholarly journals Chromosome Methylation and Measurement of Faithful, Once and Only Once per Cell Cycle Chromosome Replication inCaulobacter crescentus

1999 ◽  
Vol 181 (7) ◽  
pp. 1984-1993 ◽  
Author(s):  
Gregory T. Marczynski
Keyword(s):  
Cell Cycle ◽  
Dna Methylation ◽  
Cell Division ◽  
Dna Synthesis ◽  
Replication Origin ◽  
Asymmetric Cell Division ◽  
Caulobacter Crescentus ◽  
Chromosome Replication ◽  
Cell Stage ◽  
Swarmer Cell

ABSTRACT Caulobacter crescentus exhibits cell-type-specific control of chromosome replication and DNA methylation. Asymmetric cell division yields a replicating stalked cell and a nonreplicating swarmer cell. The motile swarmer cell must differentiate into a sessile stalked cell in order to replicate and execute asymmetric cell division. This program of cell division implies that chromosome replication initiates in the stalked cell only once per cell cycle. DNA methylation is restricted to the predivisional cell stage, and since DNA synthesis produces an unmethylated nascent strand, late DNA methylation also implies that DNA near the replication origin remains hemimethylated longer than DNA located further away. In this report, both assumptions are tested with an engineered Tn5-based transposon, Tn5Ω-MP. This allows a sensitive Southern blot assay that measures fully methylated, hemimethylated, and unmethylated DNA duplexes. Tn5Ω-MP was placed at 11 sites around the chromosome and it was clearly demonstrated that Tn5Ω-MP DNA near the replication origin remained hemimethylated longer than DNA located further away. One Tn5Ω-MP placed near the replication origin revealed small but detectable amounts of unmethylated duplex DNA in replicating stalked cells. Extra DNA synthesis produces a second unmethylated nascent strand. Therefore, measurement of unmethylated DNA is a critical test of the “once and only once per cell cycle” rule of chromosome replication inC. crescentus. Fewer than 1 in 1,000 stalked cells prematurely initiate a second round of chromosome replication. The implications for very precise negative control of chromosome replication are discussed with respect to the bacterial cell cycle.

scholarly journals The Polar Organizing Protein PopZ Is Fundamental for Proper Cell Division and Segregation of Cellular Content in Magnetospirillum gryphiswaldense

mBio ◽  
2019 ◽  
Vol 10 (2) ◽  
Author(s):  
Daniel Pfeiffer ◽  
Mauricio Toro-Nahuelpan ◽  
Marc Bramkamp ◽  
Jürgen M. Plitzko ◽  
Dirk Schüler
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Caulobacter Crescentus ◽  
Magnetotactic Bacteria ◽  
Model Organisms ◽  
Chromosomal Dna ◽  
Content Type ◽  
Magnetospirillum Gryphiswaldense ◽  
Cellular Content ◽  
Subcellular Organization

ABSTRACT Magnetotactic bacteria (MTB) are of special scientific interest due to the formation of magnetosomes, intracellular membrane-enveloped magnetite crystals arranged into a linear chain by a dedicated cytoskeleton. Magnetotaxis relies on the formation and proper inheritance of these unique magnetic organelles, both of which need to be coordinated with the segregation of other cellular content such as chromosomes or motility and chemotaxis related structures. Thus, elaborated mechanisms are required in MTB to coordinate and maintain a high level of spatial and temporal subcellular organization during cytokinesis. However, thus far, underlying mechanisms and polarity determinants such as landmark proteins remained obscure in MTB. Here, we analyzed an ortholog of the polar organizing protein Z in the alphaproteobacterium Magnetospirillum gryphiswaldense termed PopZMgr. We show that deletion of the popZMgr gene causes abnormal cell elongation, minicell formation, DNA missegregation, and impairs motility. Overproduction of PopZMgr results in PopZ-rich regions near the poles, which are devoid of larger macromolecules, such as ribosomes, chromosomal DNA, and polyhydroxybutyrate (PHB) granules. Using superresolution microscopy, we show that PopZMgr exhibits a bipolar localization pattern throughout the cell cycle, indicating that the definition of new poles in M. gryphiswaldense occurs immediately upon completion of cytokinesis. Moreover, substitution of PopZ orthologs between M. gryphiswaldense and the related alphaproteobacterium Caulobacter crescentus indicated that PopZ localization depends on host-specific cues and that both orthologs have diverged to an extent that allows only partial reciprocal functional complementation. Altogether, our results indicate that in M. gryphiswaldense, PopZ plays a critical role during cell division and segregation of cellular content. IMPORTANCE Magnetotactic bacteria (MTB) share the unique capability of magnetic navigation, one of the most complex behavioral responses found in prokaryotes, by means of magnetosomes, which act as an internal compass. Due to formation of these unique nanoparticles, MTB have emerged as a model to study prokaryotic organelle formation and cytoskeletal organization in conjunction with complex motility systems. Despite the high degree of subcellular organization required in MTB, less is known about cell-cycle-related factors or proteins responsible for spatiotemporal polarity control. Here, we investigate the function of the polar organizer PopZ in the magnetotactic alphaproteobacterium Magnetospirillum gryphiswaldense. Although PopZ is widely distributed among the alphaproteobacteria, its function in MTB belonging to this class has remained unexplored. Our results suggest that in M. gryphiswaldense, PopZ has a key role during cell division and subcellular organization. Furthermore, we show that PopZ localization and function differ from other nonmagnetotactic alphaproteobacterial model organisms.

scholarly journals Absolute Measurements of mRNA Translation inCaulobacter crescentusReveal Important Fitness Costs of Vitamin B12Scavenging

mSystems ◽  
2019 ◽  
Vol 4 (4) ◽  
Author(s):  
James R. Aretakis ◽  
Alisa Gega ◽  
Jared M. Schrader
Keyword(s):  
Cell Cycle ◽  
Protein Synthesis ◽  
Cell Division ◽  
Asymmetric Cell Division ◽  
Caulobacter Crescentus ◽  
Mrna Translation ◽  
Genetic Network ◽  
Ribosome Profiling ◽  
Content Type ◽  
Bacterial Cell Cycle

ABSTRACTCaulobacter crescentusis a model for the bacterial cell cycle which culminates in asymmetric cell division, yet little is known about the absolute levels of protein synthesis of the cellular parts needed to complete the cell cycle. Here we utilize ribosome profiling to provide absolute measurements of mRNA translation inC. crescentus, providing an important resource with quantitative genome-wide measurements of protein output across individual genes. Analysis of protein synthesis rates revealed ∼4.5% of cellular protein synthesis is for genes related to vitamin B12import (btuB) and B12-independent methionine biosynthesis (metE) when grown in common growth media lacking B12. While its facultative B12lifestyle provides a fitness advantage in the absence of B12, we find that it provides a fitness disadvantage of the cells in the presence of B12, potentially explaining why manyCaulobacterspecies have lost themetEgene and become obligates for B12.IMPORTANCECaulobacter crescentusis a model system of the bacterial cell cycle culminating in asymmetric cell division, with each daughter cell inheriting a distinct set of proteins. While a genetic network of master transcription factors coordinates the cell cycle timing of transcription for nearly 20% ofCaulobactergenes, we lack knowledge of how many of each protein “part” encoded in the genome are synthesized. Therefore, to determine the absolute production rates across the genome, we performed ribosome profiling, providing, for the first time, a quantitative resource with measurements of each protein “part” needed to generate daughter cells. This resource furthers the goal of a systems-level understanding of the genetic network controlling asymmetric cell division. To highlight the utility of this data set, we probe the protein synthesis cost of a B12utilization pathway and provide new insights intoCaulobacter’s adaptation to its natural environments.

scholarly journals Coordinating Bacterial Cell Division with Nutrient Availability: a Role for Glycolysis

mBio ◽  
2014 ◽  
Vol 5 (3) ◽  
Author(s):  
Leigh G. Monahan ◽  
Isabella V. Hajduk ◽  
Sinead P. Blaber ◽  
Ian G. Charles ◽  
Elizabeth J. Harry
Keyword(s):  
Cell Cycle ◽  
Bacillus Subtilis ◽  
Cell Division ◽  
Nutrient Availability ◽  
Pyruvate Dehydrogenase ◽  
Ring Formation ◽  
Content Type ◽  
Ring Assembly ◽  
Z Ring ◽  
Normal Division

ABSTRACTCell division in bacteria is driven by a cytoskeletal ring structure, the Z ring, composed of polymers of the tubulin-like protein FtsZ. Z-ring formation must be tightly regulated to ensure faithful cell division, and several mechanisms that influence the positioning and timing of Z-ring assembly have been described. Another important but as yet poorly understood aspect of cell division regulation is the need to coordinate division with cell growth and nutrient availability. In this study, we demonstrated for the first time that cell division is intimately linked to central carbon metabolism in the model Gram-positive bacteriumBacillus subtilis. We showed that a deletion of the gene encoding pyruvate kinase (pyk), which produces pyruvate in the final reaction of glycolysis, rescues the assembly defect of a temperature-sensitiveftsZmutant and has significant effects on Z-ring formation in wild-typeB. subtiliscells. Addition of exogenous pyruvate restores normal division in the absence of the pyruvate kinase enzyme, implicating pyruvate as a key metabolite in the coordination of bacterial growth and division. Our results support a model in which pyruvate levels are coupled to Z-ring assembly via an enzyme that actually metabolizes pyruvate, the E1α subunit of pyruvate dehydrogenase. We have shown that this protein localizes over the nucleoid in a pyruvate-dependent manner and may stimulate more efficient Z-ring formation at the cell center under nutrient-rich conditions, when cells must divide more frequently.IMPORTANCEHow bacteria coordinate cell cycle processes with nutrient availability and growth is a fundamental yet unresolved question in microbiology. Recent breakthroughs have revealed that nutritional information can be transmitted directly from metabolic pathways to the cell cycle machinery and that this can serve as a mechanism for fine-tuning cell cycle processes in response to changes in environmental conditions. Here we identified a novel link between glycolysis and cell division inBacillus subtilis. We showed that pyruvate, the final product of glycolysis, plays an important role in maintaining normal division. Nutrient-dependent changes in pyruvate levels affect the function of the cell division protein FtsZ, most likely by modifying the activity of an enzyme that metabolizes pyruvate, namely, pyruvate dehydrogenase E1α. Ultimately this system may help to coordinate bacterial division with nutritional conditions to ensure the survival of newborn cells.

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