The integral membrane FtsW protein and peptidoglycan synthase PBP3 form a subcomplex in Escherichia coli

Fraipont, Claudine; Alexeeva, Svetlana; Wolf, Benoît; Ploeg, René van der; Schloesser, Marie; Blaauwen, Tanneke den; Nguyen-Distèche, Martine

doi:10.1099/mic.0.040071-0

Cited by 111 publications

(123 citation statements)

References 43 publications

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“…We did not detect selfinteractions of FtsN and FtsI. Some of these discrepancies may be caused by the absence of the cytoplasmic and transmembrane regions that have been reported to be important for FtsI dimerization (28,29,60).…”

Section: Resultscontrasting

confidence: 65%

A New Essential Cell Division Protein in Caulobacter crescentus

et al. 2017

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Bacterial cell division is a complex process that relies on a multiprotein complex composed of a core of widely conserved and generally essential proteins and on accessory proteins that vary in number and identity in different bacteria. The assembly of this complex and, particularly, the initiation of constriction are regulated processes that have come under intensive study. In this work, we characterize the function of DipI, a protein conserved in Alphaproteobacteria and Betaproteobacteria that is essential in Caulobacter crescentus. Our results show that DipI is a periplasmic protein that is recruited late to the division site and that it is required for the initiation of constriction. The recruitment of the conserved cell division proteins is not affected by the absence of DipI, but localization of DipI to the division site occurs only after a mature divisome has formed. Yeast two-hybrid analysis showed that DipI strongly interacts with the FtsQLB complex, which has been recently implicated in regulating constriction initiation. A possible role of DipI in this process is discussed.IMPORTANCE Bacterial cell division is a complex process for which most bacterial cells assemble a multiprotein complex that consists of conserved proteins and of accessory proteins that differ among bacterial groups. In this work, we describe a new cell division protein (DipI) present only in a group of bacteria but essential in Caulobacter crescentus. Cells devoid of DipI cannot constrict. Although a mature divisome is required for DipI recruitment, DipI is not needed for recruiting other division proteins. These results, together with the interaction of DipI with a protein complex that has been suggested to regulate cell wall synthesis during division, suggest that DipI may be part of the regulatory mechanism that controls constriction initiation.KEYWORDS Caulobacter crescentus, SH3 domain, bacterial cell division, constriction initiation, divisome B acterial cell division is a complex process involving the action of a multiprotein complex known as the divisome (1, 2). In Escherichia coli, the divisome is composed of approximately 30 proteins that assemble into a complex spanning from the cytoplasm to the outer membrane (OM). Of these proteins, only 12 are essential in E. coli and 11 are widely conserved in other bacteria, suggesting that they constitute the core of the divisome (3, 4). The divisome complex starts assembling when a ring formed by the FtsZ protein is stabilized at the site where division will occur (5, 6). FtsZ is a tubulin-related cytoplasmic protein that is brought near the cytoplasmic membrane through its interactions with the membrane-associated protein FtsA and, in E. coli, the transmembrane protein ZipA (7,8). The FtsZ ring generates a force sufficient to deform lipid membranes and probably drives the constriction of the inner membrane (9, 10). After establishment of the FtsZ ring, the FtsEX complex is recruited through the interaction of FtsE with FtsZ (11). The divisome then expands to the peripla...

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Section: Resultscontrasting

confidence: 65%

A New Essential Cell Division Protein in Caulobacter crescentus

et al. 2017

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“…Together with FtsI, its linked class B penicillin-binding protein, FtsW forms a subcomplex specific for septal peptidoglycan synthesis (Fig. 1, c and d) (84). FtsI has a topology similar to FtsN: they contain a transmembrane region, followed by a long linker spanning the periplasm and a C-terminal globular domain contacting the peptidoglycan layer.…”

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confidence: 99%

In the Beginning, Escherichia coli Assembled the Proto-ring: An Initial Phase of Division

Rico

Krupka²,

Vicente

2013

Journal of Biological Chemistry

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Cell division in Escherichia coli begins by assembling three proteins, FtsZ, FtsA, and ZipA, to form a proto-ring at midcell. These proteins nucleate an assembly of at least 35 components, the divisome. The structuring of FtsZ to form a ring and the processes that effect constriction have been explained by alternative but not mutually exclusive mechanisms. We discuss how FtsA and ZipA provide anchoring of the cytoplasmic FtsZ to the membrane and how a temporal sequence of alternative protein interactions may operate in the maturation and stability of the proto-ring. How the force needed for constriction is generated and how the proto-ring proteins relate to peptidoglycan synthesis remain as the main challenges for future research. Overview of SeptationCell division is the last event in the bacterial cell cycle. It takes place by producing a rigid transversal septum after the growth processes fully duplicate the contents of the cell. Septation is always preceded by segregation of the duplicated nucleoids, ensuring that each of the daughter cells contains a fully replicated chromosome. Specialized molecules control the positioning of the division machinery at midcell, preventing any harmful fragmentation that septum progression could cause on unsegregated nucleoids.The division machinery, the divisome, establishes a complex interacting network together with DNA, lipids, and peptidoglycan components. It comprises a variable number of proteins, depending on the bacterial species. These proteins have redundant multiple functions and connections serving as safeguards to complete division and to guarantee the efficiency and versatility of the process. Altogether, an efficient division process allows the proliferation of bacteria under a variety of conditions, and it is one of the reasons for their success in the environment. Free-living bacteria, such as Escherichia coli, have more elaborated divisomes, whereas those that need to grow as intracellular parasites, as such Mycoplasma genitalium, have streamlined ones (1, 2).The structure of the E. coli divisome as revealed by immunofluorescence images of dividing cells is called the division ring (3). For its assembly, three essential proteins, FtsZ, FtsA, and ZipA, are first gathered at midcell, forming a proto-ring attached to the inner membrane ( Fig. 1) (4). In the proto-ring structure, the cytoplasmic GTPase FtsZ is anchored to the membrane by its interaction with ZipA and FtsA. ZipA is a bitopic protein containing a transmembrane domain (5). FtsA is a protein of the actin family that associates with the membrane by a short amphipathic helix (6, 7). The assembly of the FtsZ ring is dependent on a continuous energy supply. The FtsZ ring requires either ZipA or FtsA (8). Although it can be formed in the presence of either of them, division is affected unless both are present (9). A maturation period takes place after the protoring is assembled and before the rest of the divisome proteins become incorporated (10). During maturation, the proto-ring assembly is not stable...

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“…To generate FLIM-FRET constructs, the mCherry coding sequence was amplified from the pSAV047 vector (Fraipont et al, 2011) and cloned at the KpnI/SacI sites of the P35S:SR45-GFP vector to replace the GFP coding sequence. To generate the P35S:mCherry-GFP control, the amplicon was also ligated in P35S:SR34-GFP at the BamHI/KpnI sites to replace the SR34 coding sequence.…”

Section: Binary Vector Constructionsmentioning

confidence: 99%

Dynamic Distribution and Interaction of the Arabidopsis SRSF1 Subfamily Splicing Factors

Stankovic¹,

Schloesser²,

Joris³

et al. 2015

Plant Physiology

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Ser/Arg-rich (SR) proteins are essential nucleus-localized splicing factors. Our prior studies showed that Arabidopsis (Arabidopsis thaliana) RSZ22, a homolog of the human SRSF7 SR factor, exits the nucleus through two pathways, either dependent or independent on the XPO1 receptor. Here, we examined the expression profiles and shuttling dynamics of the Arabidopsis SRSF1 subfamily (SR30, SR34, SR34a, and SR34b) under control of their endogenous promoter in Arabidopsis and in transient expression assay. Due to its rapid nucleocytoplasmic shuttling and high expression level in transient assay, we analyzed the multiple determinants that regulate the localization and shuttling dynamics of SR34. By site-directed mutagenesis of SR34 RNA-binding sequences and Arg/Ser-rich (RS) domain, we further show that functional RRM1 or RRM2 are dispensable for the exclusive protein nuclear localization and speckle-like distribution. However, mutations of both RRMs induced aggregation of the protein whereas mutation in the RS domain decreased the stability of the protein and suppressed its nuclear accumulation. Furthermore, the RNA-binding motif mutants are defective for their export through the XPO1 (CRM1/ Exportin-1) receptor pathway, but retain nucleocytoplasmic mobility. We performed a yeast two hybrid screen with SR34 as bait and discovered SR45 as a new interactor. SR45 is an unusual SR splicing factor bearing two RS domains. These interactions were confirmed in planta by FLIM-FRET and BiFC and the roles of SR34 domains in protein-protein interactions were further studied. Altogether, our report extends our understanding of shuttling dynamics of Arabidopsis SR splicing factors.

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The integral membrane FtsW protein and peptidoglycan synthase PBP3 form a subcomplex in Escherichia coli

Cited by 111 publications

References 43 publications

A New Essential Cell Division Protein in Caulobacter crescentus

A New Essential Cell Division Protein in Caulobacter crescentus

In the Beginning, Escherichia coli Assembled the Proto-ring: An Initial Phase of Division

Dynamic Distribution and Interaction of the Arabidopsis SRSF1 Subfamily Splicing Factors

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