Spatiotemporal control of PopZ localization through cell cycle–coupled multimerization

Laloux, Géraldine; Jacobs‐Wagner, Christine

doi:10.1083/jcb.201303036

Cited by 91 publications

(152 citation statements)

References 36 publications

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“…4A), as previously reported (29,31). Throughout extended PopZ polar zones, ParA G16V -eYFP was robustly recruited, creating large regions of colocalization with ParA fluorescence (Fig.…”

Section: Resultssupporting

confidence: 54%

“…6B) (18,19). It was proposed that ParA accumulation at the new pole during segregation could stimulate the formation of a new complex of PopZ at this position (29). Here we observe that popZ alleles defective for ParA binding are not significantly defective in bipolar PopZ complex formation.…”

Section: Discussionsupporting

confidence: 59%

“…Together, these results are consistent with a model in which robust interactions between PopZ and ParA are required for proper functioning of the ParA centromere segregation machine. displace large objects such as ribosomes and nucleoid DNA but allow smaller molecules to enter (18,19,29,31). This suggests that the filamentous PopZ structure forms a 3D microenvironment near the pole that is distinct from the general cytoplasm.…”

Section: Resultsmentioning

confidence: 96%

“…However, in wild-type cells after segregation, significantly more ParA accumulates at the new pole than at the old (20), which may suggest a synergistic effect of PopZ and TipN on ParA recruitment or modulation, conceivably via a handoff of free ParA from TipN to PopZ. Recently, Laloux and Jacobs-Wagner (29) showed that PopZ recruitment to the new pole is significantly delayed in cells lacking TipN. In light of our data, we hypothesize that segregation defects in ΔtipN strains could result in part from such a delay in positioning a PopZ complex at the new pole, which would prevent PopZ from directing ParA reassembly to terminate segregation.…”

Section: Discussionmentioning

confidence: 99%

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Bacterial scaffold directs pole-specific centromere segregation

Ptacin¹,

Gahlmann

Bowman³

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

156

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Bacteria use partitioning systems based on the ParA ATPase to actively mobilize and spatially organize molecular cargoes throughout the cytoplasm. The bacterium Caulobacter crescentus uses a ParA-based partitioning system to segregate newly replicated chromosomal centromeres to opposite cell poles. Here we demonstrate that the Caulobacter PopZ scaffold creates an organizing center at the cell pole that actively regulates polar centromere transport by the ParA partition system. As segregation proceeds, the ParB-bound centromere complex is moved by progressively disassembling ParA from a nucleoid-bound structure. Using superresolution microscopy, we show that released ParA is recruited directly to binding sites within a 3D ultrastructure composed of PopZ at the cell pole, whereas the ParB-centromere complex remains at the periphery of the PopZ structure. PopZ recruitment of ParA stimulates ParA to assemble on the nucleoid near the PopZ-proximal cell pole. We identify mutations in PopZ that allow scaffold assembly but specifically abrogate interactions with ParA and demonstrate that PopZ/ParA interactions are required for proper chromosome segregation in vivo. We propose that during segregation PopZ sequesters free ParA and induces target-proximal regeneration of ParA DNA binding activity to enforce processive and pole-directed centromere segregation, preventing segregation reversals. PopZ therefore functions as a polar hub complex at the cell pole to directly regulate the directionality and destination of transfer of the mitotic segregation machine.

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“…4A), as previously reported (29,31). Throughout extended PopZ polar zones, ParA G16V -eYFP was robustly recruited, creating large regions of colocalization with ParA fluorescence (Fig.…”

Section: Resultssupporting

confidence: 54%

Section: Discussionsupporting

confidence: 59%

Section: Resultsmentioning

confidence: 96%

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Bacterial scaffold directs pole-specific centromere segregation

Ptacin¹,

Gahlmann

Bowman³

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

156

View full text Add to dashboard Cite

show abstract

“…One such protein is the polar scaffold PopZ, which interacts with the ParB/parS complex to enable directional chromosome segregation (18,19). PopZ is positioned at the stalked cell pole early in the cell cycle and forms a second focus at the opposite pole upon the initiation of replication and segregation of the chromosome to anchor the translocated centromere to the new cell pole (18)(19)(20)(21). To determine whether replication-independent translocation of ParB/parS is accompanied by the assembly of a second PopZ focus at the new cell pole, we constructed a popZ merodiploid derived from the P vanA -dnaA depletion strain containing CFP-ParB and expressing a xylose-inducible allele of popZ fused to mCherry.…”

Section: Replication-independent Translocation Of the Centromere Requmentioning

confidence: 99%

Replication initiator DnaA binds at the Caulobacter centromere and enables chromosome segregation

Mera

Kalogeraki

Shapiro

2014

Proc. Natl. Acad. Sci. U.S.A.

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Significance DnaA is an essential and conserved bacterial protein that enables the initiation of DNA replication. Although it is commonly held that the onset of bacterial chromosome segregation depends on the initiation of DNA replication, we have found that in Caulobacter crescentus , chromosome segregation can be induced in a DnaA-dependent, yet replication-independent manner. The chromosome replication origin, containing essential DnaA binding motifs, resides 8 kb from the centromere parS region that also contains DnaA binding motifs. The centromere parS region bound to the ParB partition protein initiates movement across the cell followed by the origin region. Mutations in a centromere DnaA motif that alter DnaA–centromere interaction exhibit aberrant patterns of ParB/ parS translocation, implicating DnaA in the process of chromosome segregation.

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Nucleotide‐independent cytoskeletal scaffolds in bacteria

Lin

Thanbichler

2013

Cytoskeleton

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Bacteria possess a diverse set of cytoskeletal proteins that mediate key cellular processes such as morphogenesis, cell division, DNA segregation, and motility. Similar to eukaryotic actin or tubulin, many of them require nucleotide binding and hydrolysis for proper polymerization and function. However, there is also a growing number of bacterial cytoskeletal elements that assemble in a nucleotide-independent manner, including intermediate filament-like structures as well several classes of bacteria-specific polymers. The members of this group form stable scaffolds that have architectural roles or act as localization factors recruiting other proteins to distinct positions within the cell. Here, we highlight the elements that constitute the nucleotideindependent cytoskeleton of bacteria and discuss their biological functions in different species. V C 2013 Wiley Periodicals, Inc.

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Spatiotemporal control of PopZ localization through cell cycle–coupled multimerization

Abstract: ParA-dependent DNA segregation determines the cell cycle localization pattern of the pole-organizing protein PopZ by promoting its assembly into a matrix.

Cited by 91 publications

References 36 publications

Bacterial scaffold directs pole-specific centromere segregation

Bacterial scaffold directs pole-specific centromere segregation

Replication initiator DnaA binds at the Caulobacter centromere and enables chromosome segregation

Nucleotide‐independent cytoskeletal scaffolds in bacteria

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