Structure and function of bacterial dynamin-like proteins

Bramkamp, Marc

doi:10.1515/hsz-2012-0185

Cited by 58 publications

(59 citation statements)

References 77 publications

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“…G1, G2 and G3 are further highly conserved motifs that together form a catalytic center; while G4 and G5 motifs ensure specificity for GTP binding [48]. A role in base binding is ascribed to the G4 motif (usually N/TKxD, though mitofusins contain R instead of K) [49]. The side chain of Asn258 interacts with the base through the hydrogen bond, as expected.…”

Section: Resultsmentioning

confidence: 96%

“…Two former symmetry-mated unit regions are placed in close proximity to the guanosine part of the ligand, the latter to the phosphate part. The exact moment and purpose of GTP hydrolysis along the MFN2 activity path is yet to be elucidated [49]. We hypothesize that those three regions might take part in cooperative GTP hydrolysis and represent the first step in the homodimer formation process.…”

Section: Discussionmentioning

confidence: 99%

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The Effect of a Novel c.820C>T (Arg274Trp) Mutation in the Mitofusin 2 Gene on Fibroblast Metabolism and Clinical Manifestation in a Patient

et al. 2017

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Charcot-Marie-Tooth disease type 2A (CMT2A) is an autosomal dominant axonal peripheral neuropathy caused by mutations in the mitofusin 2 gene (MFN2). Mitofusin 2 is a GTPase protein present in the outer mitochondrial membrane and responsible for regulation of mitochondrial network architecture via the fusion of mitochondria. As that fusion process is known to be strongly dependent on the GTPase activity of mitofusin 2, it is postulated that the MFN2 mutation within the GTPase domain may lead to impaired GTPase activity, and in turn to mitochondrial dysfunction. The work described here has therefore sought to verify the effects of MFN2 mutation within its GTPase domain on mitochondrial and endoplasmic reticulum morphology, as well as the mtDNA content in a cultured primary fibroblast obtained from a CMT2A patient harboring a de novo Arg274Trp mutation. In fact, all the parameters studied were affected significantly by the presence of the mutant MFN2 protein. However, using the stable model for mitofusin 2 obtained by us, we were next able to determine that the Arg274Trp mutation does not impact directly upon GTP binding. Such results were also confirmed for GTP-hydrolysis activity of MFN2 protein in patient fibroblast. We therefore suggest that the biological malfunctions observable with the disease are not consequences of impaired GTPase activity, but rather reflect an impaired contribution of the GTPase domain to other MFN2 activities involving that region, for example protein-protein interactions.

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Section: Resultsmentioning

confidence: 96%

Section: Discussionmentioning

confidence: 99%

The Effect of a Novel c.820C>T (Arg274Trp) Mutation in the Mitofusin 2 Gene on Fibroblast Metabolism and Clinical Manifestation in a Patient

et al. 2017

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“…The general tandem encoding of bacterial DLPs suggests some form of cooperation between the two proteins [34]. Since dynamin-like proteins form stalk and GTPase-domain dimers that associate to polymerise into large structures, it seems likely that the two dynamin-like proteins always occurring in a single operon in bacteria may generally form heterodimers.…”

Section: Discussionmentioning

confidence: 99%

LeoA, B and C from Enterotoxigenic Escherichia coli (ETEC) Are Bacterial Dynamins

et al. 2014

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Escherichia coli (ETEC) strain H10407 contains a GTPase virulence factor, LeoA, which is encoded on a pathogenicity island and has been shown to enhance toxin release, potentially through vesicle secretion. By sequence comparisons and X-ray structure determination we now identify LeoA as a bacterial dynamin-like protein (DLP). Proteins of the dynamin family remodel membranes and were once thought to be restricted to eukaryotes. In ETEC H10407 LeoA localises to the periplasm where it forms a punctate localisation pattern. Bioinformatic analyses of leoA and the two upstream genes leoB and leoC suggest that LeoA works in concert with a second dynamin-like protein, made up of LeoB and LeoC. Disruption of the leoAB genes leads to a reduction in secretion of periplasmic Tat-GFP and outer membrane OmpA. Our data suggest a role for LeoABC dynamin-like proteins in potentiating virulence through membrane vesicle associated toxin secretion.

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“…They share a conserved domain architecture with the canonical human Dynamin 1, including the N-terminal GTPase domain, a neck domain involved in dynamin dimerization, and a trunk domain involved in stimulation of GTPase activity (4,5). In contrast, bacterial dynamins lack the pleckstrin homology motif and proline-rich sequences found in classical dynamins and contain instead other lipidand protein-binding motifs (5).…”

mentioning

confidence: 99%

Two dynamin-like proteins stabilize FtsZ rings during Streptomyces sporulation

Schlimpert

Wasserström

Chandra

et al. 2017

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

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During sporulation, the filamentous bacteria Streptomyces undergo a massive cell division event in which the synthesis of ladders of sporulation septa convert multigenomic hyphae into chains of unigenomic spores. This process requires cytokinetic Z-rings formed by the bacterial tubulin homolog FtsZ, and the stabilization of the newly formed Z-rings is crucial for completion of septum synthesis. Here we show that two dynamin-like proteins, DynA and DynB, play critical roles in this process. Dynamins are a family of large, multidomain GTPases involved in key cellular processes in eukaryotes, including vesicle trafficking and organelle division. Many bacterial genomes encode dynamin-like proteins, but the biological function of these proteins has remained largely enigmatic. Using a cell biological approach, we show that the two Streptomyces dynamins specifically localize to sporulation septa in an FtsZ-dependent manner. Moreover, dynamin mutants have a cell division defect due to the decreased stability of sporulation-specific Z-rings, as demonstrated by kymographs derived from time-lapse images of FtsZ ladder formation. This defect causes the premature disassembly of individual Z-rings, leading to the frequent abortion of septum synthesis, which in turn results in the production of long spore-like compartments with multiple chromosomes. Two-hybrid analysis revealed that the dynamins are part of the cell division machinery and that they mediate their effects on Z-ring stability during developmentally controlled cell division via a network of protein-protein interactions involving DynA, DynB, FtsZ, SepF, SepF2, and the FtsZ-positioning protein SsgB.he active organization and remodeling of cellular membranes is a fundamental process for all organisms. Many of these remodeling events involve the reshaping, fission, or fusion of lipid bilayers to generate new organelles, release transport vesicles, or stabilize specific membrane structures. In eukaryotes, key cellular processes, such as the fission and fusion of mitochondria, the division of chloroplasts, endocytosis, and viral resistance, are mediated by members of the dynamin superfamily (1). Dynamins and dynamin-like proteins are mechanochemical GTPases that polymerize into helical scaffolds at the surface of membranes. GTP hydrolysis is coupled to a radical conformational change in the protein structure that forces the underlying lipid layer into an energetically unstable conformation that promotes membrane rearrangements, probably via a hemifusion intermediate (2, 3).Dynamin-like proteins are found in many bacterial species, yet the precise roles of these proteins are still largely unknown. They share a conserved domain architecture with the canonical human Dynamin 1, including the N-terminal GTPase domain, a neck domain involved in dynamin dimerization, and a trunk domain involved in stimulation of GTPase activity (4, 5). In contrast, bacterial dynamins lack the pleckstrin homology motif and proline-rich sequences found in classical dynamins and contain instead o...

show abstract

Structure and function of bacterial dynamin-like proteins

Cited by 58 publications

References 77 publications

The Effect of a Novel c.820C>T (Arg274Trp) Mutation in the Mitofusin 2 Gene on Fibroblast Metabolism and Clinical Manifestation in a Patient

The Effect of a Novel c.820C>T (Arg274Trp) Mutation in the Mitofusin 2 Gene on Fibroblast Metabolism and Clinical Manifestation in a Patient

LeoA, B and C from Enterotoxigenic Escherichia coli (ETEC) Are Bacterial Dynamins

Two dynamin-like proteins stabilize FtsZ rings during Streptomyces sporulation

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