The Interactions of Cell Division Protein FtsZ with Guanine Nucleotides

Huecas, Sonia; Schaffner-Barbero, Claudia; Garcia, Wânius; Yébenes, Hugo; Palacios, J.M.; Díaz, J. Fernando; Menéndez, Margarita; Andreu, José Manuel

doi:10.1074/jbc.m706399200

Cited by 72 publications

(103 citation statements)

References 58 publications

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“…Depolymerization experiments carried out in solution (14) have also determined that GTPase hydrolysis rate is faster than depolymerization, but in such bulk experiments monomer exchange and monomer release cannot be isolated as independent processes, and therefore their association to GTP hydrolysis or exchange is ambiguous. Biochemical data suggesting nucleotide exchange into protofilaments are available (14,(21)(22)(23)(24), supporting our interpretation that both nucleotide exchange and hydrolysis are determining the observed depolymerization dynamics.…”

Section: Discussionsupporting

confidence: 69%

Depolymerization dynamics of individual filaments of bacterial cytoskeletal protein FtsZ

Mateos-Gil

Paez²,

Hörger³

et al. 2012

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

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We report observation and analysis of the depolymerization filaments of the bacterial cytoskeletal protein FtsZ (filament temperature-sensitive Z) formed on a mica surface. At low concentration, proteins adsorbed on the surface polymerize forming curved filaments that close into rings that remain stable for some time before opening irreversibly and fully depolymerizing. The distribution of ring lifetimes (T ) as a function of length (N), shows that the rate of ring aperture correlates with filament length. If this ring lifetime is expressed as a bond survival time, (T b ≡ NT), this correlation is abolished, indicating that these rupture events occur randomly and independently at each monomer interface. After rings open irreversibly, depolymerization of the remaining filaments is fast, but can be slowed down and followed using a nonhydrolyzing GTP analogue. The histogram of depolymerization velocities of individual filaments has an asymmetric distribution that can be fit with a computer model that assumes two rupture rates, a slow one similar to the one observed for ring aperture, affecting monomers in the central part of the filaments, and a faster one affecting monomers closer to the open ends. From the quantitative analysis, we conclude that the depolymerization rate is affected both by nucleotide hydrolysis rate and by its exchange along the filament, that all monomer interfaces are equally competent for hydrolysis, although depolymerization is faster at the open ends than in central filament regions, and that all monomer-monomer interactions, regardless of the nucleotide present, can adopt a curved configuration.bacterial division | atomic force microscopy | computer simulations | GTP hydrolysis B acterial cytoskeletal protein FtsZ (filamenting temperaturesensitive Z) assembles into dynamic polymers on the inner side of the bacterial cytoplasmic membrane in the presence of GTP. Its role in cell division is twofold: recruiting the rest of the proteins involved in the assembly of the septal ring and contributing to generate the force needed for cell rupture. Recent in vitro experiments with artificially membrane-bound FtsZ reconstituted in model systems support the suggestion that FtsZ is capable of generating a contractile force without the need of any other proteins (1, 2). Several theoretical models trying to explain the molecular mechanism by which the GTP-dependent self-assembling polymerization process generates a contractile force have been recently proposed (3-12), but the debate is still open. Existing controversy over the relative contribution of filament curvature and lateral interactions in the constriction process is difficult to resolve until new experimental data determine how GTP hydrolysis is associated to monomer exchange within filaments.FtsZ is known to polymerize above a critical concentration in the presence of GTP (13). Bulk experiments in solution using a fluorescence signal to follow polymerization (14) have provided indirect evidence of monomer exchange, annealing, and depolymerizatio...

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Section: Discussionsupporting

confidence: 69%

Depolymerization dynamics of individual filaments of bacterial cytoskeletal protein FtsZ

Mateos-Gil

Paez²,

Hörger³

et al. 2012

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

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“…2B). Because buried SASA provides a qualitative estimate for the strength of monomer-monomer association, the consistently lower SASA values observed for the GDP-FtsZ dimer are in accordance with prior results showing that assembly of GDP-FtsZ is weaker than GTP-FtsZ, and that hydrolysis destabilizes FtsZ filaments (15,(26)(27)(28). It is likely that hydrolysis of GTP transitions a relatively straight GTP-FtsZ filament to one that can take on a highly curved conformation while decreasing the association strength between monomers, leading to a filament more prone to depolymerization.…”

supporting

confidence: 77%

Nucleotide-dependent conformations of FtsZ dimers and force generation observed through molecular dynamics simulations

Hsin

Gopinathan

Huang

2012

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

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The bacterial cytoskeletal protein FtsZ is a GTPase that is thought to provide mechanical constriction force via an unidentified mechanism. Purified FtsZ polymerizes into filaments with varying structures in vitro: while GTP-bound FtsZ assembles into straight or gently curved filaments, GDP-bound FtsZ forms highly curved filaments, prompting the hypothesis that a difference in the inherent curvature of FtsZ filaments provides mechanical force. However, no nucleotide-dependent structural transition of FtsZ monomers has been observed to support this force generation model. Here, we present a series of all-atom molecular dynamics simulations probing the effects of nucleotide binding on the structure of an FtsZ dimer. We found that the FtsZ-dimer structure is dependent on nucleotidebinding state. While a GTP-bound FtsZ dimer retained a firm monomer-monomer contact, a GDP-bound FtsZ dimer lost some of the monomer-monomer association, leading to a "hinge-opening" event that resulted in a more bent dimer, while leaving each monomer structure largely unaffected. We constructed models of FtsZ filaments and found that a GDP-FtsZ filament is much more curved than a GTP-FtsZ filament, with the degree of curvature matching prior experimental data. FtsZ dynamics were used to estimate the amount of force an FtsZ filament could exert when hydrolysis occurs (20-30 pN per monomer). This magnitude of force is sufficient to direct inward cell-wall growth during division, and to produce the observed degree of membrane pinching in liposomes. Taken together, our data provide molecular-scale insight on the origin of FtsZ-based constriction force, and the mechanism underlying prokaryotic cell division.bacterial cell division | bacterial cytoskeleton | GTP hydrolysis T he bacterial cell-division protein FtsZ, a tubulin homolog and a GTPase, polymerizes into filaments situated underneath the cytoplasmic membrane at the division site (1-3). The ftsz gene is essential and depletion of FtsZ protein leads to cells unable to divide that instead take on a filamentous morphology (4). During division, rod-shaped bacteria such as Escherichia coli synthesize new hemispherical membrane and cell wall, requiring inward forces. While an array of proteins are needed for division to occur (5, 6), FtsZ alone has been demonstrated to be sufficient for generating inward pinching forces on liposomes in vitro (7-10), and is thought to be the source of the constriction force needed for division.How FtsZ generates mechanical force is still unclear, but several models have been proposed (11), one of which is based on the intrinsic nucleotide-dependent bending of FtsZ filaments (12, 13). In the presence of GTP, purified FtsZ assembles into either straight or gently curved filaments with a radius of curvature of approximately 100 nm, while in the presence of GDP, highly curved filaments form with a radius of curvature of approximately 10 nm (12,14,15). Subsequent theoretical modeling demonstrated that the rapid transition between straight and curved FtsZ filaments...

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“…Nucleotide 3 H]GTP concentration in the protein-depleted top and bottom solution halves from 200-l polycarbonate tubes after centrifugation at 386,000 ϫ g (100,000 rpm) for 2 h in the TL100 rotor at 25°C, correcting for the small amount of nucleotide sedimented in the absence of protein (35).…”

Section: CMmentioning

confidence: 99%

Bacterial Tubulin Distinct Loop Sequences and Primitive Assembly Properties Support Its Origin from a Eukaryotic Tubulin Ancestor

Martín-Galiano

Oliva

Sanz

et al. 2011

Journal of Biological Chemistry

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The structure of the unique bacterial tubulin BtubA/B from Prosthecobacter is very similar to eukaryotic ␣␤-tubulin but, strikingly, BtubA/B fold without eukaryotic chaperones. Our sequence comparisons indicate that BtubA and BtubB do not really correspond to either ␣-or ␤-tubulin but have mosaic sequences with intertwining features from both. Their nucleotide-binding loops are more conserved, and their more divergent sequences correspond to discrete surface zones of tubulin involved in microtubule assembly and binding to eukaryotic cytosolic chaperonin, which is absent from the Prosthecobacter dejongeii draft genome. BtubA/B cooperatively assembles over a wider range of conditions than ␣␤-tubulin, forming pairs of protofilaments that coalesce into bundles instead of microtubules, and it lacks the ability to differentially interact with divalent cations and bind typical tubulin drugs. Assembled BtubA/B contain close to one bound GTP and GDP. Both BtubA and BtubB subunits hydrolyze GTP, leading to disassembly. The mutant BtubA/B-S144G in the tubulin signature motif GGG(T/ S)G(S/T)G has strongly inhibited GTPase, but BtubA-T147G/B does not, suggesting that BtubB is a more active GTPase, like ␤-tubulin. BtubA/B chimera bearing the ␤-tubulin loops M, H1-S2, and S9-S10 in BtubB fold, assemble, and have reduced GTPase activity. However, introduction of the ␣-tubulin loop S9-S10 with its unique eight-residue insertion impaired folding. From the sequence analyses, its primitive assembly features, and the properties of the chimeras, we propose that BtubA/B were acquired shortly after duplication of a spontaneously folding ␣-and ␤-tubulin ancestor, possibly by horizontal gene transfer from a primitive eukaryotic cell, followed by divergent evolution.

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The Interactions of Cell Division Protein FtsZ with Guanine Nucleotides

Cited by 72 publications

References 58 publications

Depolymerization dynamics of individual filaments of bacterial cytoskeletal protein FtsZ

Depolymerization dynamics of individual filaments of bacterial cytoskeletal protein FtsZ

Nucleotide-dependent conformations of FtsZ dimers and force generation observed through molecular dynamics simulations

Bacterial Tubulin Distinct Loop Sequences and Primitive Assembly Properties Support Its Origin from a Eukaryotic Tubulin Ancestor

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