<b>DivIB, FtsZ and cell division in <i>Bacillus subtilis</i></b>

Rowland, Susan; Katis, V.L.; Partridge, Sally R.; Wake, R.G.

doi:10.1046/j.1365-2958.1997.2141580.x

Cited by 34 publications

(54 citation statements)

References 24 publications

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“…Thus, the number of PrsA molecules adjacent to the translocase could be limiting in spite of an apparent large overall excess. Alternatively, such an excess may be advantageous for the cell under some growth conditions, as has been demonstrated in the case of the DivIB cell division protein: much higher levels of DivIB are needed for normal growth at 47°C than at 30°C (40). Our findings also suggest that overexpression of PrsA is beneficial not only in biotechnical applications in which a secreted protein saturates the secretion apparatus (23) but also at lower levels of expression.…”

Section: Discussionsupporting

confidence: 52%

Quantitation of the Capacity of the Secretion Apparatus and Requirement for PrsA in Growth and Secretion of α-Amylase in Bacillus subtilis

et al. 2001

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Regulated expression of AmyQ ␣-amylase of Bacillus amyloliquefaciens was used to examine the capacity of the protein secretion apparatus of B. subtilis. One B. subtilis cell was found to secrete maximally 10 fg of AmyQ per h. The signal peptidase SipT limits the rate of processing of the signal peptide. Another limit is set by PrsA lipoprotein. The wild-type level of PrsA was found to be 2 ؋ 10 4 molecules per cell. Decreasing the cellular level of PrsA did not decrease the capacity of the protein translocation or signal peptide processing steps but dramatically affected secretion in a posttranslocational step. There was a linear correlation between the number of cellular PrsA molecules and the number of secreted AmyQ molecules over a wide range of prsA and amyQ expression levels. Significantly, even when amyQ was expressed at low levels, overproduction of PrsA enhanced its secretion. The finding is consistent with a reversible interaction between PrsA and AmyQ. The high cellular level of PrsA suggests a chaperone-like function. PrsA was also found to be essential for the viability of B. subtilis. Drastic depletion of PrsA resulted in altered cellular morphology and ultimately in cell death.Proteins synthesized with a signal peptide are secreted from bacterial cells by the action of the protein secretion apparatus, which consists of several components involved in protein targeting, translocation, signal peptide processing, and posttranslocational folding (4, 7). Extensive studies of Escherichia coli and Bacillus subtilis have identified and characterized to a substantial extent the components of the apparatus that translocates secretory proteins across the cytoplasmic membrane. In B. subtilis, they include the SecY, SecE, and SecG proteins, which form the core of the translocation channel or translocator (30,47) and are associated in the membrane with the SecDF protein (3). Furthermore, there are several signal peptidases (43, 45). The role of SecA ATPase on the cis side of the membrane in targeting and coupling the energy required for translocation has been well established (15,48). Many components of the secretion apparatus are known to be under temporal control; their maximal level of expression parallels the onset of protein secretion in the early stationary growth phase (15, 43).The stages of protein secretion that take place outside the cytoplasmic membrane are less well understood. A central feature of secretion is posttranslocational folding. The correct folding of many secreted proteins is not spontaneous but dependent on assisting folding factors. In E. coli they include protein-specific chaperones, periplasmic peptidyl-prolyl cis/trans isomerases, and enzymes (Dsb proteins) involved in the formation and rearrangement of disulfide bonds (8,16,19,31,32). The depletion of foldases such as SurA and PpiD causes misfolding stress that activates the E -and cpx-dependent stress response (5,6,31). This results in the induction of expression of the periplasmic protease and foldases (6, 37), often resulting in t...

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Section: Discussionsupporting

confidence: 52%

Quantitation of the Capacity of the Secretion Apparatus and Requirement for PrsA in Growth and Secretion of α-Amylase in Bacillus subtilis

et al. 2001

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“…B. subtilis has a probable homologue of ftsQ called divIB (11,76), but some of the properties of DivIB highlight possible differences in function. First, as with FtsA (see above), DivIB appears to be much more abundant (about 100-fold more) than its E. coli counterpart (147). Second, mutants with null mutations of divIB are viable, although they are temperature sensitive and fail to divide at higher temperatures (11).…”

Section: Ftsq/divibmentioning

confidence: 99%

Cytokinesis in Bacteria

Errington

Daniel

Scheffers

2003

Microbiol Mol Biol Rev

556

601

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Work on two diverse rod-shaped bacteria, Escherichia coli and Bacillus subtilis, has defined a set of about 10 conserved proteins that are important for cell division in a wide range of eubacteria. These proteins are directed to the division site by the combination of two negative regulatory systems. Nucleoid occlusion is a poorly understood mechanism whereby the nucleoid prevents division in the cylindrical part of the cell, until chromosome segregation has occurred near midcell. The Min proteins prevent division in the nucleoid-free spaces near the cell poles in a manner that is beginning to be understood in cytological and biochemical terms. The hierarchy whereby the essential division proteins assemble at the midcell division site has been worked out for both E. coli and B. subtilis. They can be divided into essentially three classes depending on their position in the hierarchy and, to a certain extent, their subcellular localization. FtsZ is a cytosolic tubulin-like protein that polymerizes into an oligomeric structure that forms the initial ring at midcell. FtsA is another cytosolic protein that is related to actin, but its precise function is unclear. The cytoplasmic proteins are linked to the membrane by putative membrane anchor proteins, such as ZipA of E. coli and possibly EzrA of B. subtilis, which have a single membrane span but a cytoplasmic C-terminal domain. The remaining proteins are either integral membrane proteins or transmembrane proteins with their major domains outside the cell. The functions of most of these proteins are unclear with the exception of at least one penicillin-binding protein, which catalyzes a key step in cell wall synthesis in the division septum

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“…This suggests that DivIC is recruited to the septum site earlier than or together with DivIB at 30°C, but at 49°C, DivIB is required to maintain DivIC at the division site, perhaps by direct interaction. A role for DivIB in promoting division complex assembly at higher temperatures has been proposed previously (12,24). It has been proposed that FtsL and DivIC interact directly (8).…”

mentioning

confidence: 99%

Septal Localization of the Membrane-Bound Division Proteins of Bacillus subtilis DivIB and DivIC Is Codependent Only at High Temperatures and Requires FtsZ

2000

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Using immunofluorescence microscopy, we have examined the dependency of localization among three Bacillus subtilis division proteins, FtsZ, DivIB, and DivIC, to the division site. DivIC is required for DivIB localization. However, DivIC localization is dependent on DivIB only at high growth temperatures, at which DivIB is essential for division. FtsZ localization is required for septal recruitment of DivIB and DivIC, but FtsZ can be recruited independently of DivIB. These localization studies suggest a more specific role for DivIB in division, involving interaction with DivIC.It is very likely that a large protein complex forms at the division site in bacteria (20,23,25). To elucidate the molecular mechanism of cell division, an understanding of how this complex forms and functions is necessary. In Escherichia coli, morphogenetic evidence suggests that the various division proteins are required at different stages of septation: for example, FtsZ and FtsW act early, while FtsA, FtsQ, and FtsI are required for septal elongation and closure (21). Consistent with the order of action of division proteins, FtsZ localizes first, then FtsA and ZipA localize independently of each other (2,10,19), and the remaining membrane-bound proteins assemble in the following order: FtsK (26), FtsQ (6), FtsL (9), PBP 3 (FtsI) (28), and FtsN (1). It is unclear precisely when FtsW localizes in this sequence. In these localization dependency studies, no two division proteins were interdependent for septal recruitment, strongly suggesting that in E. coli, proteins are recruited to the division site in a strict linear sequence (28).In Bacillus subtilis there is no ZipA or FtsN homolog. FtsZ and three membrane-bound division proteins, DivIB (FtsQ homolog) (11), DivIC (FtsL-like) (14, 16), and PBP 2B (PBP 3 homolog) (29), have been shown to localize to the division site (7,13,14,17,27). All of these proteins appear to be required early in septation (5,7,8,12,16), although PBP 2B is additionally required for the duration of septal ingrowth (7). As in E. coli, FtsZ probably assembles early since Z rings can form at midcell in the absence of detectable localization of FtsL, DivIC, DivIB, or PBP 2B at 37°C (7,8,17,18). However, the septal recruitment pathway for the membrane-bound division proteins in B. subtilis appears to be different from that in E. coli. FtsL depletion at 37°C results in rapid degradation of DivIC, while DivIB and PBP 2B localizations are undetectable, suggesting that all three proteins localize either after FtsL or together with FtsL (7,8). Such division protein instability in the absence of another division protein has not been demonstrated in E. coli, suggesting that the septation process, or at least the assembly of the division complex, is regulated somewhat differently in the two organisms. Surprisingly, when PBP 2B is depleted at 37°C, DivIB and DivIC localizations are significantly decreased and occur only at midfilament positions, probably at incomplete septa (7). In contrast, in E. coli the PBP 2B homolog, PBP 3, ...

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DivIB, FtsZ and cell division in Bacillus subtilis

Cited by 34 publications

References 24 publications

Quantitation of the Capacity of the Secretion Apparatus and Requirement for PrsA in Growth and Secretion of α-Amylase in Bacillus subtilis

Quantitation of the Capacity of the Secretion Apparatus and Requirement for PrsA in Growth and Secretion of α-Amylase in Bacillus subtilis

Cytokinesis in Bacteria

Septal Localization of the Membrane-Bound Division Proteins of Bacillus subtilis DivIB and DivIC Is Codependent Only at High Temperatures and Requires FtsZ

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