An autoinhibitory conformation of the<i>Bacillus subtilis</i>spore coat protein SpoIVA prevents its premature ATP-independent aggregation

Castaing, Jean-Philippe; Lee, Scarlett; Anantharaman, Vivek; Ravilious, Geoffrey E.; Aravind, L.; Ramamurthi, Kumaran S.

doi:10.1111/1574-6968.12452

Cited by 19 publications

(18 citation statements)

References 31 publications

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“…A fourth spontaneous mutation in clpP , that altered a residue near the hydrophobic binding pocket that mediates ClpP’s interaction with ClpX, also suppressed the sporulation defect caused by cmpA overexpression. Involvement of SpoIVA as a target for degradation by ClpXP arose from two mutations in adjacent codons of spoIVA that altered residues between the Middle and C-terminal domain of SpoIVA (Castaing et al, 2014), suppressed the sporulation defect of the spoVM I15A allele (which arrests sporulation in a CmpA-dependent manner) and led to stabilization of SpoIVA.…”

Section: Discussionmentioning

confidence: 99%

A Quality-Control Mechanism Removes Unfit Cells from a Population of Sporulating Bacteria

et al. 2015

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SUMMARY Recent discoveries of regulated cell death in bacteria have led to speculation about possible benefits that apoptosis-like pathways may confer to single-celled organisms. However, establishing how these pathways provide increased ecological fitness has remained difficult to determine. Here, we report a pathway in Bacillus subtilis in which regulated cell death maintains the fidelity of sporulation through selective removal of cells that misassemble the spore envelope. The spore envelope, which protects the dormant spore’s genome from environmental insults, uses the protein SpoIVA as a scaffold for assembly. We found that disrupting envelope assembly activates a cell death pathway wherein the small protein CmpA acts as an adaptor to the AAA+ ClpXP protease to degrade SpoIVA, thereby halting sporulation and resulting in lysis of defective sporulating cells. We propose that removal of unfit cells from a population of terminally differentiating cells protects against evolutionary deterioration, and ultimately loss, of the sporulation program.

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Section: Discussionmentioning

confidence: 99%

A Quality-Control Mechanism Removes Unfit Cells from a Population of Sporulating Bacteria

et al. 2015

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“…Since previous work with B. subtilis SpoIVA revealed that ATP binding to SpoIVA induces a conformational change that allows SpoIVA to self-polymerize upon hydrolyzing ATP (34,41), we sought to test whether ATP binding and/or hydrolysis were required for C. difficile SipL to recognize SpoIVA during spore formation. Since the ATPase activity of B. subtilis SpoIVA is also required for SpoIVA to fully encase the forespore (34), we wondered how disrupting conserved ATPase motifs in C. difficile SpoIVA would impact spore coat assembly.…”

Section: Introductionmentioning

confidence: 99%

Role of SpoIVA ATPase Motifs DuringClostridioides difficileSporulation

Puebla

Giacalone

Cooper³

et al. 2020

Preprint

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AbstractThe nosocomial pathogen, Clostridioides difficile, is a spore-forming obligate anaerobe that depends on its aerotolerant spore form to transmit infections. Functional spore formation depends on the assembly of a proteinaceous layer known as the coat around the developing spore. In C. difficile, coat assembly depends on the conserved coat protein, SpoIVA, and the clostridial-specific coat protein, SipL, which directly interact. Mutations that disrupt their interaction cause coat to mislocalize and decrease functional spore formation. In B. subtilis, SpoIVA is an ATPase that uses ATP hydrolysis to help drive its polymerization around the forespore. Loss of SpoIVA ATPase activity impairs B. subtilis SpoIVA encasement of the forespore and activates a quality control mechanism that eliminates these defective cells. Since this mechanism is lacking in C. difficile, we tested whether mutations in C. difficile’s SpoIVA ATPase motifs impair functional spore formation. Disrupting C. difficile SpoIVA ATPase motifs resulted in phenotypes that were typically >104 less severe than the equivalent mutations in B. subtilis. Interestingly, mutation of ATPase motif residues predicted to abrogate SpoIVA binding to ATP decreased SpoIVA-SipL interaction, whereas mutation of ATPase motif residues predicted to disrupt ATP hydrolysis but retain binding to ATP enhanced SpoIVA-SipL interaction. When a sipL mutation known to reduce binding to SpoIVA was combined with a spoIVA mutation predicted to prevent SpoIVA binding to ATP, spore formation was severely exacerbated. Since this phenotype is allele-specific, our data implies that SipL recognizes the ATP-bound form of SpoIVA and highlights the importance of this interaction for functional C. difficile spore formation.ImportanceThe aerotolerant spores formed by the major nosocomial pathogen Clostridioides difficile are its primary infectious particle. However, the mechanism by which this critical cell type is assembled remains poorly characterized, especially with respect to its protective coat layer. We previously showed that binding between the spore morphogenetic proteins, SpoIVA and SipL, regulates coat assembly around the forespore. SpoIVA is widely conserved among spore-forming bacteria, and its ATPase activity is essential for Bacillus subtilis to form functional spores. In this study, we determined that mutations in C. difficile SpoIVA’s ATPase motifs result in relatively minor defects in spore formation in contrast with B. subtilis. Nevertheless, our data suggest that SipL preferentially recognizes the ATP-bound form of SpoIVA and identify a specific residue in SipL’s C-terminal LysM domain that is critical for recognizing the ATP-bound form of SpoIVA. These findings advance our understanding of how SpoIVA-SipL interactions regulate C. difficile spore assembly.

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“…A tough proteinaceous shell (the "coat") composed of proteins made in the outer "mother cell" is built around the forespore and protects the genetic material in the dormant spore from environmental insults (13). Assembly of the coat begins with a basement layer (14,15), the structural protein of which is an unusual cytoskeletal protein that polymerizes into a static structure via a mechanism requiring both ATP binding and ATP hydrolysis (14,(16)(17)(18)(19). This protein is anchored onto the surface of the forespore (20) by the small (26 aa) amphipathic α-helical protein SpoVM (21)(22)(23).…”

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confidence: 99%

Structural basis for the geometry-driven localization of a small protein

Gill

Castaing

Hsin

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

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In bacteria, certain shape-sensing proteins localize to differently curved membranes. During sporulation in Bacillus subtilis, the only convex (positively curved) surface in the cell is the forespore, an approximately spherical internal organelle. Previously, we demonstrated that SpoVM localizes to the forespore by preferentially adsorbing onto slightly convex membranes. Here, we used NMR and molecular dynamics simulations of SpoVM and a localization mutant (SpoVM P9A ) to reveal that SpoVM's atypical amphipathic α-helix inserts deeply into the membrane and interacts extensively with acyl chains to sense packing differences in differently curved membranes. Based on binding to spherical supported lipid bilayers and Monte Carlo simulations, we hypothesize that SpoVM's membrane insertion, along with potential cooperative interactions with other SpoVM molecules in the lipid bilayer, drives its preferential localization onto slightly convex membranes. Such a mechanism, which is distinct from that used by high curvature-sensing proteins, may be widely conserved for the localization of proteins onto the surface of cellular organelles.ArfGAP1 | SpoIVA | DivIVA | curvature sensing | lipid packing

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An autoinhibitory conformation of theBacillus subtilisspore coat protein SpoIVA prevents its premature ATP-independent aggregation

Cited by 19 publications

References 31 publications

A Quality-Control Mechanism Removes Unfit Cells from a Population of Sporulating Bacteria

A Quality-Control Mechanism Removes Unfit Cells from a Population of Sporulating Bacteria

Role of SpoIVA ATPase Motifs DuringClostridioides difficileSporulation

Structural basis for the geometry-driven localization of a small protein

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