Dual localization pathways for the engulfment proteins during <i>Bacillus subtilis</i> sporulation

Aung, Stefan; Shum, Jonathan; Mello, Angelica Abanes-De; Broder, Dan H.; Fredlund-Gutierrez, Jennifer; Chiba, Shinobu; Pogliano, Kit

doi:10.1111/j.1365-2958.2007.05887.x

Cited by 40 publications

(71 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This implies that an additional mechanism promotes fission during sporulation. Possible candidates include peptidoglycan synthesis as proposed by Dworkin and colleagues (Meyer et al 2010) or peptidoglycan hydrolysis carried out by the membrane-anchored peptidoglycan hydrolase complex composed of SpoIID, SpoIIP, and SpoIIM (Abanes-De Mello et al 2002;Aung et al 2007;Morlot et al 2010). Either of these machines could bring the engulfing membranes into close proximity and promote fission (Judd et al 2005), although at a slower rate than FisB.…”

Section: Discussionmentioning

confidence: 99%

FisB mediates membrane fission during sporulation in Bacillus subtilis

et al. 2013

View full text Add to dashboard Cite

How bacteria catalyze membrane fission during growth and differentiation is an outstanding question in prokaryotic cell biology. Here, we describe a protein (FisB, for fission protein B) that mediates membrane fission during the morphological process of spore formation in Bacillus subtilis. Sporulating cells divide asymmetrically, generating a large mother cell and smaller forespore. After division, the mother cell membranes migrate around the forespore in a phagocytic-like process called engulfment. Membrane fission releases the forespore into the mother cell cytoplasm. Cells lacking FisB are severely and specifically impaired in the fission reaction. Moreover, GFP-FisB forms dynamic foci that become immobilized at the site of fission. Purified FisB catalyzes lipid mixing in vitro and is only required in one of the fusing membranes, suggesting that FisB-lipid interactions drive membrane remodeling. Consistent with this idea, the extracytoplasmic domain of FisB binds with remarkable specificity to cardiolipin, a lipid enriched in the engulfing membranes and regions of negative curvature. We propose that membrane topology at the final stage of engulfment and FisB-cardiolipin interactions ensure that the mother cell membranes are severed at the right time and place. The unique properties of FisB set it apart from the known fission machineries in eukaryotes, suggesting that it represents a new class of fission proteins.

show abstract

Section: Discussionmentioning

confidence: 99%

FisB mediates membrane fission during sporulation in Bacillus subtilis

et al. 2013

View full text Add to dashboard Cite

show abstract

“…Since IID and IIP are present in a complex at the site of PG hydrolysis (Abanes-De Mello et al 2002;Aung et al 2007;Chastanet and Losick 2007), we wondered whether IID activity requires IIP. To test this, we incubated the two purified proteins with the RBB dye-coupled PG.…”

Section: Iid Activity Requires Iipmentioning

confidence: 99%

“…All three proteins are synthesized in the mother immediately after polar cell division is complete and localize to the center of the septum, where degradation of the septal PG is initiated (Abanes-De Mello et al 2002;Aung et al 2007;Chastanet and Losick 2007). Once the enzyme complexes arrive at the cell periphery, they appear to localize at the leading edge of the engulfing septal membrane (Fig.…”

mentioning

confidence: 99%

“…1A). IIM is predicted to have five transmembrane segments and is thought to serve as a scaffold for the assembly of the IID-IIP-IIM complex (Aung et al 2007;Chastanet and Losick 2007). Cells lacking any one of these proteins are blocked at the earliest stage of the engulfment process: the degradation of the septal PG resident between the mother cell and forespore.…”

mentioning

confidence: 99%

See 1 more Smart Citation

A highly coordinated cell wall degradation machine governs spore morphogenesis in Bacillus subtilis

Morlot¹,

Uehara²,

Marquis³

et al. 2010

Genes Dev.

146

View full text Add to dashboard Cite

How proteins catalyze morphogenesis is an outstanding question in developmental biology. In bacteria, morphogenesis is intimately linked to remodeling the cell wall exoskeleton. Here, we investigate the mechanisms by which the mother cell engulfs the prospective spore during sporulation in Bacillus subtilis. A membraneanchored protein complex containing two cell wall hydrolases plays a central role in this morphological process. We demonstrate that one of the proteins (SpoIIP) has both amidase and endopeptidase activities, such that it removes the stem peptides from the cell wall and cleaves the cross-links between them. We further show that the other protein (SpoIID) is the founding member of a new family of lytic transglycosylases that degrades the glycan strands of the peptidoglycan into disaccharide units. Importantly, we show that SpoIID binds the cell wall, but will only cleave the glycan strands after the stem peptides have been removed. Finally, we demonstrate that SpoIID also functions as an enhancer of SpoIIP activity. Thus, this membrane-anchored enzyme complex is endowed with complementary, sequential, and stimulatory activities. These activities provide a mechanism for processive cell wall degradation, supporting a model in which circumferentially distributed degradation machines function as motors pulling the mother cell membranes around the forespore.[Keywords: Morphogenesis; cell shape; peptidoglycan; sporulation; amidase; lytic transglycosylase] Supplemental material is available at http://www.genesdev.org.

show abstract

“…These studies failed to demonstrate an interaction between SpoIIM and either SpoIID or SpoIIP, perhaps because SpoIIM is an integral membrane protein. However, SpoIIM is required for localization of SpoIID and SpoIIP (2,8), suggesting that all three proteins interact to form a peptidoglycan degradation module that is essential for engulfment.The second system influencing membrane migration is the SpoIIQ/SpoIIIAH zipper, which is required for engulfment only under certain conditions (2,7,38). SpoIIQ is produced in the forespore (23) and SpoIIIAH is produced in the mother cell (19).…”

mentioning

confidence: 99%

SpoIID-Mediated Peptidoglycan Degradation Is Required throughout Engulfment during Bacillus subtilis Sporulation

2010

Self Cite

View full text Add to dashboard Cite

SpoIID is a membrane-anchored enzyme that degrades peptidoglycan and is essential for engulfment and sporulation in Bacillus subtilis. SpoIID is targeted to the sporulation septum, where it interacts with two other proteins required for engulfment: SpoIIP and SpoIIM. We changed conserved amino acids in SpoIID to alanine to determine whether there was a correlation between the effect of each substitution on the in vivo and in vitro activities of SpoIID. We identified one amino acid substitution, E88A, that eliminated peptidoglycan degradation activity and one, D210A, that reduced it, as well as two substitutions that destabilized the protein in B. subtilis (R106A and K203A). Using these mutants, we show that the peptidoglycan degradation activity of SpoIID is required for the first step of engulfment (septal thinning), as well as throughout membrane migration, and we show that SpoIID levels are substantially above the minimum required for engulfment. The inactive mutant E88A shows increased septal localization compared to the wild type, suggesting that the degradation cycle of the SpoIID/SpoIIP complex is accompanied by the activity-dependent release of SpoIID from the complex and subsequent rebinding. This mutant is also capable of moving SpoIIP across the sporulation septum, suggesting that SpoIID binding, but not peptidoglycan degradation activity, is needed for relocalization of SpoIIP. Finally, the mutant with reduced activity (D210A) causes uneven engulfment and time-lapse microscopy indicates that the fastest-moving membrane arm has greater concentrations of SpoIIP than the slower-moving arm, demonstrating a correlation between SpoIIP protein levels and the rate of membrane migration.Endospore formation is an evolutionarily conserved process that allows Bacillus subtilis and related Gram-positive bacteria to adapt to changes in the environment, such as nutrient depletion. Many dramatic morphological changes occur during sporulation, each requiring a multitude of specialized proteins (reviewed in references 13 and 17). First, a sporulation septum is formed near one of the cell poles, forming two separate compartments of unequal sizes and with differing fates (Fig. 1A). The smaller of the two, the forespore, will eventually become the spore, while the larger, the mother cell, will ultimately lyse. Next, the mother cell membranes move up and around the forespore in the poorly understood process of engulfment. Although this process is superficially similar to eukaryotic engulfment, it is complicated by the thick cell wall that surrounds and separates the two compartments. After engulfment, the migrating membranes pinch off from the mother cell membrane, thereby releasing the forespore into the cytoplasm of the mother cell, where it can be enveloped with protective coat proteins and eventually released into the environment as a mature spore. Sporulation provides an ideal, nonessential system for understanding how bacterial cells are capable of undergoing dramatic morphological changes.Engulfment involves dynam...

show abstract

Dual localization pathways for the engulfment proteins during Bacillus subtilis sporulation

Cited by 40 publications

References 40 publications

FisB mediates membrane fission during sporulation in Bacillus subtilis

FisB mediates membrane fission during sporulation in Bacillus subtilis

A highly coordinated cell wall degradation machine governs spore morphogenesis in Bacillus subtilis

SpoIID-Mediated Peptidoglycan Degradation Is Required throughout Engulfment during Bacillus subtilis Sporulation

Contact Info

Product

Resources

About