scholarly journals FisB relies on homo-oligomerization and lipid binding to catalyze membrane fission in bacteria

PLoS Biology ◽  
2021 ◽  
Vol 19 (6) ◽  
pp. e3001314
Author(s):  
Ane Landajuela ◽  
Martha Braun ◽  
Christopher D. A. Rodrigues ◽  
Alejandro Martínez-Calvo ◽  
Thierry Doan ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Mother Cell ◽  
Negative Curvature ◽  
Lipid Binding ◽  
Membrane Curvature ◽  
Membrane Topology ◽  
Cell Cytoplasm ◽  
Curvature Sensing ◽  
Membrane Fission ◽  
Late Stages

Little is known about mechanisms of membrane fission in bacteria despite their requirement for cytokinesis. The only known dedicated membrane fission machinery in bacteria, fission protein B (FisB), is expressed during sporulation in Bacillus subtilis and is required to release the developing spore into the mother cell cytoplasm. Here, we characterized the requirements for FisB-mediated membrane fission. FisB forms mobile clusters of approximately 12 molecules that give way to an immobile cluster at the engulfment pole containing approximately 40 proteins at the time of membrane fission. Analysis of FisB mutants revealed that binding to acidic lipids and homo-oligomerization are both critical for targeting FisB to the engulfment pole and membrane fission. Experiments using artificial membranes and filamentous cells suggest that FisB does not have an intrinsic ability to sense or induce membrane curvature but can bridge membranes. Finally, modeling suggests that homo-oligomerization and trans-interactions with membranes are sufficient to explain FisB accumulation at the membrane neck that connects the engulfment membrane to the rest of the mother cell membrane during late stages of engulfment. Together, our results show that FisB is a robust and unusual membrane fission protein that relies on homo-oligomerization, lipid binding, and the unique membrane topology generated during engulfment for localization and membrane scission, but surprisingly, not on lipid microdomains, negative-curvature lipids, or curvature sensing.

scholarly journals The bacterial membrane fission protein FisB requires homo-oligomerization and lipid-binding to catalyze membrane scission

2020 ◽  
Author(s):  
Ane Landajuela ◽  
Martha Braun ◽  
Christopher D. A. Rodrigues ◽  
Thierry Doan ◽  
Florian Horenkamp ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Mother Cell ◽  
Negative Curvature ◽  
Lipid Binding ◽  
Membrane Topology ◽  
Bacterial Membrane ◽  
Cell Cytoplasm ◽  
Lipid Microdomains ◽  
Membrane Fission ◽  
Membrane Scission

ABSTRACTLittle is known about mechanisms of membrane fission in bacteria despite their requirement for cytokinesis. The only known dedicated membrane fission machinery in bacteria, FisB, is expressed during sporulation in Bacillus subtilis and is required to release the developing spore into the mother cell cytoplasm. Here we characterized the requirements for FisB-mediated membrane fission. FisB forms mobile clusters of ~12 molecules that give way to an immobile cluster at the engulfment pole containing ~40 proteins at the time of membrane fission. Function mutants revealed that binding to acidic lipids and homo-oligomerization are both critical for targeting FisB to the engulfment pole and membrane fission. Our results suggest that FisB is a robust and unusual membrane fission protein that relies on homo-oligomerization, lipid-binding and likely the unique membrane topology generated during engulfment for localization and membrane scission, but surprisingly, not on lipid microdomains or negative-curvature lipids.

scholarly journals Processing of a Membrane Protein Required for Cell-to-Cell Signaling during Endospore Formation in Bacillus subtilis

2008 ◽  
Vol 190 (23) ◽  
pp. 7786-7796 ◽  
Author(s):  
Mónica Serrano ◽  
Filipe Vieira ◽  
Charles P. Moran ◽  
Adriano O. Henriques
Keyword(s):  
Bacillus Subtilis ◽  
Membrane Protein ◽  
Signal Peptide ◽  
Sigma Factor ◽  
Mother Cell ◽  
Membrane System ◽  
Cell Cytoplasm ◽  
Double Membrane ◽  
Sec System ◽  
System Activation

ABSTRACT Activation of the late prespore-specific RNA polymerase sigma factor σG during Bacillus subtilis sporulation coincides with completion of the engulfment process, when the prespore becomes a protoplast fully surrounded by the mother cell cytoplasm and separated from it by a double membrane system. Activation of σG also requires expression of spoIIIJ, coding for a membrane protein translocase of the YidC/Oxa1p/Alb3 family, and of the mother cell-specific spoIIIA operon. Here we present genetic and biochemical evidence indicating that SpoIIIAE, the product of one of the spoIIIA cistrons, and SpoIIIJ interact in the membrane, thereby linking the function of the spoIIIJ and spoIIIA loci in the activation of σG. We also show that SpoIIIAE has a functional Sec-type signal peptide, which is cleaved during sporulation. Furthermore, mutations that reduce or eliminate processing of the SpoIIIAE signal peptide arrest sporulation following engulfment completion and prevent activation of σG. SpoIIIJ-type proteins can function in cooperation with or independently of the Sec system. In one model, SpoIIIJ interacts with SpoIIIAE in the context of the Sec translocon to promote its correct localization and/or topology in the membrane, so that it can signal the activation of σG following engulfment completion.

Quantitative investigation of negative membrane curvature sensing and generation by I-BARs in filopodia of living cells

Soft Matter ◽  
2019 ◽  
Vol 15 (48) ◽  
pp. 9829-9839 ◽  
Author(s):  
Artù Breuer ◽  
Line Lauritsen ◽  
Elena Bertseva ◽  
Ivana Vonkova ◽  
Dimitrios Stamou
Keyword(s):  
Negative Curvature ◽  
Living Cells ◽  
Membrane Curvature ◽  
Quantitative Investigation ◽  
Curvature Sensing ◽  
Bar Domains

We analyze diffraction-limited filopodia of living cells to quantify negative curvature sensing and generation for two prototypic I-BAR domains.

scholarly journals Membrane fission during bacterial spore development requires DNA-driven cellular inflation

2021 ◽  
Author(s):  
Ane Landajuela ◽  
Martha Braun ◽  
Alejandro Martinez-Calvo ◽  
Christopher D. A. Rodrigues ◽  
Thierry Doan ◽  
...  
Keyword(s):  
Cell Division ◽  
Mother Cell ◽  
Complete Genome ◽  
Molecular Basis ◽  
Membrane Tension ◽  
Dna Translocation ◽  
Cell Cytoplasm ◽  
Membrane Fission ◽  
Catalyzed Membrane ◽  
Dna Translocase

Bacteria require membrane fission for cell division and endospore formation. FisB catalyzes membrane fission during sporulation, but the molecular basis is unclear as it cannot remodel membranes by itself. Sporulation initiates with an asymmetric division that generates a large mother cell and a smaller forespore that contains only 1/4 of its complete genome. As the mother cell membranes engulf the forespore, a DNA translocase pumps the rest of the chromosome into the small forespore compartment, inflating it due to increased turgor. When the engulfing membranes undergo fission, the forespore is released into the mother cell cytoplasm. Here we show that forespore inflation and FisB accumulation are both required for efficient membrane fission. We suggest that high membrane tension in the engulfment membrane caused by forespore inflation drives FisB-catalyzed membrane fission. Collectively our data indicate that DNA-translocation has a previously unappreciated second function in energizing FisB-mediated membrane fission under energy-limited conditions.

scholarly journals Membrane curvature sensing by the C-terminal domain of complexin

2014 ◽  
Vol 5 (1) ◽  
Author(s):  
David Snead ◽  
Rachel T. Wragg ◽  
Jeremy S. Dittman ◽  
David Eliezer
Keyword(s):  
Membrane Curvature ◽  
Curvature Sensing ◽  
Terminal Domain

Membrane curvature and the control of GTP hydrolysis in Arf1 during COPI vesicle formation

2005 ◽  
Vol 33 (4) ◽  
pp. 619-622 ◽  
Author(s):  
B. Antonny ◽  
J. Bigay ◽  
J.-F. Casella ◽  
G. Drin ◽  
B. Mesmin ◽  
...  
Keyword(s):  
Lipid Membranes ◽  
Membrane Curvature ◽  
Gtp Hydrolysis ◽  
Membrane Fission ◽  
Transport Vesicles ◽  
Highly Sensitive ◽  
Copi Vesicle ◽  
Membrane Budding ◽  
Gtpase Cycle ◽  
Adp Ribosylation Factor

The GTP switch of the small G-protein Arf1 (ADP-ribosylation factor 1) on lipid membranes promotes the polymerization of the COPI (coat protein complex I) coat, which acts as a membrane deforming shell to form transport vesicles. Real-time measurements for coat assembly on liposomes gives insights into how the GTPase cycle of Arf1 is coupled in time with the polymerization of the COPI coat and the resulting membrane deformation. One key parameter seems to be the membrane curvature. Arf-GAP1 (where GAP stands for GTPase-activating protein), which promotes GTP hydrolysis in the Arf1–COPI complex is highly sensitive to lipid packing. Its activity on Arf1-GTP increases by two orders of magnitude as the diameter of the liposomes approaches that of authentic transport vesicles (60 nm). This suggests that during membrane budding, Arf1-GTP molecules are progressively eliminated from the coated area where the membrane curvature is positive, but are protected from Arf-GAP1 at the bud neck due to the negative curvature of this region. As a result, the coat should be stable as long as the bud remains attached and should disassemble as soon as membrane fission occurs.

scholarly journals A dynamic, ring-forming MucB / RseB-like protein influences spore shape in Bacillus subtilis

PLoS Genetics ◽  
2020 ◽  
Vol 16 (12) ◽  
pp. e1009246
Author(s):  
Johana Luhur ◽  
Helena Chan ◽  
Benson Kachappilly ◽  
Ahmed Mohamed ◽  
Cécile Morlot ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Fluorescence Microscopy ◽  
Mother Cell ◽  
Morphological Changes ◽  
Cell Envelope ◽  
Genetic Relationships ◽  
Protein Domain ◽  
Phenotypic Characterization ◽  
Spore Coat ◽  
3D Fluorescence Microscopy

How organisms develop into specific shapes is a central question in biology. The maintenance of bacterial shape is connected to the assembly and remodelling of the cell envelope. In endospore-forming bacteria, the pre-spore compartment (the forespore) undergoes morphological changes that result in a spore of defined shape, with a complex, multi-layered cell envelope. However, the mechanisms that govern spore shape remain poorly understood. Here, using a combination of fluorescence microscopy, quantitative image analysis, molecular genetics and transmission electron microscopy, we show that SsdC (formerly YdcC), a poorly-characterized new member of the MucB / RseB family of proteins that bind lipopolysaccharide in diderm bacteria, influences spore shape in the monoderm Bacillus subtilis. Sporulating cells lacking SsdC fail to adopt the typical oblong shape of wild-type forespores and are instead rounder. 2D and 3D-fluorescence microscopy suggest that SsdC forms a discontinuous, dynamic ring-like structure in the peripheral membrane of the mother cell, near the mother cell proximal pole of the forespore. A synthetic sporulation screen identified genetic relationships between ssdC and genes involved in the assembly of the spore coat. Phenotypic characterization of these mutants revealed that spore shape, and SsdC localization, depend on the coat basement layer proteins SpoVM and SpoIVA, the encasement protein SpoVID and the inner coat protein SafA. Importantly, we found that the ΔssdC mutant produces spores with an abnormal-looking cortex, and abolishing cortex synthesis in the mutant largely suppresses its shape defects. Thus, SsdC appears to play a role in the proper assembly of the spore cortex, through connections to the spore coat. Collectively, our data suggest functional diversification of the MucB / RseB protein domain between diderm and monoderm bacteria and identify SsdC as an important factor in spore shape development.

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