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

2000 ◽  
Vol 182 (12) ◽  
pp. 3607-3611 ◽  
Author(s):  
V. L. Katis ◽  
R. G. Wake ◽  
E. J. Harry
Keyword(s):  
Bacillus Subtilis ◽  
High Temperatures ◽  
Immunofluorescence Microscopy ◽  
High Growth ◽  
Specific Role ◽  
Ofbacillus Subtilis ◽  
Division Site ◽  
Membrane Bound ◽  
Septal Localization

ABSTRACT Using immunofluorescence microscopy, we have examined the dependency of localization among three Bacillus subtilisdivision 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.

scholarly journals Septal Localization of Penicillin-Binding Protein 1 in Bacillus subtilis

1999 ◽  
Vol 181 (10) ◽  
pp. 3201-3211 ◽  
Author(s):  
Lotte B. Pedersen ◽  
Esther R. Angert ◽  
Peter Setlow
Keyword(s):  
Bacillus Subtilis ◽  
Immunofluorescence Microscopy ◽  
Binding Protein ◽  
Divalent Cations ◽  
Significant Proportion ◽  
Growth Media ◽  
Weight Class ◽  
Penicillin Binding Protein ◽  
Septal Localization ◽  
Mutant Cells

ABSTRACT Previous studies have shown that Bacillus subtiliscells lacking penicillin-binding protein 1 (PBP1), encoded byponA, have a reduced growth rate in a variety of growth media and are longer, thinner, and more bent than wild-type cells. It was also recently shown that cells lacking PBP1 require increased levels of divalent cations for growth and are either unable to grow or grow as filaments in media low in Mg2+, suggesting a possible involvement of PBP1 in septum formation under these conditions. Using epitope-tagging and immunofluorescence microscopy, we have now shown that PBP1 is localized at division sites in vegetative cells of B. subtilis. In addition, we have used fluorescence and electron microscopy to show that growingponA mutant cells display a significant septation defect, and finally by immunofluorescence microscopy we have found that while FtsZ localizes normally in most ponA mutant cells, a significant proportion of ponA mutant cells display FtsZ rings with aberrant structure or improper localization, suggesting that lack of PBP1 affects FtsZ ring stability or assembly. These results provide strong evidence that PBP1 is localized to and has an important function in the division septum in B. subtilis. This is the first example of a high-molecular-weight class A PBP that is localized to the bacterial division septum.

scholarly journals Cell Division in Bacillus subtilis: FtsZ and FtsA Association Is Z-Ring Independent, and FtsA Is Required for Efficient Midcell Z-Ring Assembly

2005 ◽  
Vol 187 (18) ◽  
pp. 6536-6544 ◽  
Author(s):  
S. O. Jensen ◽  
L. S. Thompson ◽  
E. J. Harry
Keyword(s):  
Bacillus Subtilis ◽  
Cell Division ◽  
Ring Formation ◽  
Division Site ◽  
Ring Assembly ◽  
Synchronous Cell ◽  
Z Ring ◽  
Membrane Bound ◽  
Chemical Cross Linking

ABSTRACT The earliest stage in cell division in bacteria is the assembly of a Z ring at the division site at midcell. Other division proteins are also recruited to this site to orchestrate the septation process. FtsA is a cytosolic division protein that interacts directly with FtsZ. Its function remains unknown. It is generally believed that FtsA localization to the division site occurs immediately after Z-ring formation or concomitantly with it and that FtsA is responsible for recruiting the later-assembling membrane-bound division proteins to the division site. Here, we report the development of an in vivo chemical cross-linking assay to examine the association between FtsZ and FtsA in Bacillus subtilis cells. We subsequently use this assay in a synchronous cell cycle to show that these two proteins can interact prior to Z-ring formation. We further show that in a B. subtilis strain containing an ftsA deletion, FtsZ localized at regular intervals along the filament but the majority of Z rings were abnormal. FtsA in this organism is therefore critical for the efficient formation of functional Z rings. This is the first report of abnormal Z-ring formation resulting from the loss of a single septation protein. These results suggest that in this organism, and perhaps others, FtsA ensures recruitment of the membrane-bound division proteins by ensuring correct formation of the Z ring.

scholarly journals Membrane-Bound Division Proteins DivIB and DivIC ofBacillus subtilis Function Solely through Their External Domains in both Vegetative and Sporulation Division

1999 ◽  
Vol 181 (9) ◽  
pp. 2710-2718 ◽  
Author(s):  
Vittorio L. Katis ◽  
R. Gerry Wake
Keyword(s):  
Escherichia Coli ◽  
The Other ◽  
Wild Type ◽  
Transmembrane Segment ◽  
Ofbacillus Subtilis ◽  
Transmembrane Segments ◽  
Terminal Domain ◽  
Division Site ◽  
Membrane Bound ◽  
Type Gene

ABSTRACT The Bacillus subtilis membrane-bound division proteins, DivIB and DivIC, each contain a single transmembrane segment flanked by a short cytoplasmic N-terminal domain and a larger external C-terminal domain. Both proteins become localized at the division site prior to septation. Mutagenesis of both divIB and divICwas performed whereby the sequences encoding the cytoplasmic domains were replaced by the corresponding sequence of the other gene. Finally, the cytoplasmic-plus-transmembrane-encoding domain of each protein was replaced by a totally foreign sequence not involved in division, that encodes the N-terminal-plus-transmembrane domains of theEscherichia coli TolR protein. B. subtilisstrains expressing the divIB and divIC hybrids, in the absence of the wild-type gene, were viable when grown under conditions in which the wild-type genes were found previously to be essential. Furthermore, these strains were able to sporulate to near normal levels. Thus, the cytoplasmic and transmembrane segments of DivIB and DivIC do not appear to have any specific functions other than to anchor these proteins correctly in the membrane. The implications of these findings are discussed.

scholarly journals Lipid droplets maintain lipid homeostasis during anaphase for efficient cell separation in budding yeast

2016 ◽  
Vol 27 (15) ◽  
pp. 2368-2380 ◽  
Author(s):  
Po-Lin Yang ◽  
Tzu-Han Hsu ◽  
Chao-Wen Wang ◽  
Rey-Huei Chen
Keyword(s):  
Cell Separation ◽  
Neutral Lipids ◽  
Budding Yeast ◽  
Acid Synthesis ◽  
Mitotic Exit ◽  
Lipid Homeostasis ◽  
Physiological Conditions ◽  
Division Site ◽  
Quadruple Mutant ◽  
Membrane Bound

The neutral lipids steryl ester and triacylglycerol (TAG) are stored in the membrane-bound organelle lipid droplet (LD) in essentially all eukaryotic cells. It is unclear what physiological conditions require the mobilization or storage of these lipids. Here, we study the budding yeast mutant are1Δ are2Δ dga1Δ lro1Δ, which cannot synthesize the neutral lipids and therefore lacks LDs. This quadruple mutant is delayed at cell separation upon release from mitotic arrest. The cells have abnormal septa, unstable septin assembly during cytokinesis, and prolonged exocytosis at the division site at the end of cytokinesis. Lipidomic analysis shows a marked increase of diacylglycerol (DAG) and phosphatidic acid, the precursors for TAG, in the mutant during mitotic exit. The cytokinesis and separation defects are rescued by adding phospholipid precursors or inhibiting fatty acid synthesis, which both reduce DAG levels. Our results suggest that converting excess lipids to neutral lipids for storage during mitotic exit is important for proper execution of cytokinesis and efficient cell separation.

scholarly journals The FtsH Protein Accumulates at the Septum ofBacillus subtilis during Cell Division and Sporulation

2000 ◽  
Vol 182 (13) ◽  
pp. 3870-3873 ◽  
Author(s):  
Wolfgang Wehrl ◽  
Michael Niederweis ◽  
Wolfgang Schumann
Keyword(s):  
Bacillus Subtilis ◽  
Cell Division ◽  
Cytoplasmic Membrane ◽  
Point Mutations ◽  
Filamentous Growth ◽  
Coding Region ◽  
Enhanced Fluorescence ◽  
Ofbacillus Subtilis ◽  
Transmembrane Segments ◽  
Dividing Cells

ABSTRACT The ftsH gene encodes an ATP- and Zn2+-dependent metalloprotease which is anchored to the cytoplasmic membrane via two transmembrane segments in such a way that the very short amino- and the long carboxy termini are exposed to the cytoplasm. Deletion of the ftsH gene in Bacillus subtilis results in a pleiotropic phenotype such as filamentous growth. This observation prompted us to ask whether ftsH is involved in cell division. A translational fusion was constructed between the complete coding region of ftsH andgfp + the latter carrying five point mutations to obtain enhanced fluorescence. We detected that the FtsH protein accumulates in the midcell septum of dividing cells, and during sporulation first in the asymmetrically located septa of sporulating cells and later in the membrane which engulfs the forespore. These observations revealed a new function of FtsH.

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