title: A bacterial dynamin-like protein mediating nucleotide-independent membrane fusion.
abstract: Dynamins are a family of large GTPases that are involved in key cellular processes, where they mediate events of membrane fission and fusion. The dynamin superfamily is not restricted to eukaryotes but might have a bacterial origin, with many species containing an operon of two genes related to mitofusins. However, it is not clear whether bacterial dynamins promote membrane fission or fusion. The dynamin-like protein DynA of Bacillus subtilis is remarkable in that it arose from a gene fusion of two dynamins and contains two separate dynamin-like subunits and GTPase domains. We found that DynA exhibits strictly auto-regulated GTP hydrolysis, and that progress through the GTPase cycle is concerted within DynA oligomers. Furthermore, we show that DynA can tether membranes and mediates nucleotide-independent membrane fusion in vitro. This process merely requires magnesium as a cofactor. Our results provide a set of minimal requirements for membrane fusion by dynamin-like proteins and have mechanistic implications in particular for the fusion of mitochondria.
authors.affiliation: Institute for Biochemistry, University of Cologne, Zülpicherstr. 47, 50674 Köln, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Bürmann
authors.forename: Nina
authors.initials: N
authors.lastname: Ebert
authors.forename: Suey
authors.initials: S
authors.lastname: van Baarle
authors.forename: Marc
authors.initials: M
authors.lastname: Bramkamp
mesh_terms: D001412:Bacillus subtilis / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics / Q000502:physiology; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D034281:Dynamins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000378:metabolism; D008561:Membrane Fusion; D008928:Mitochondria / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D009711:Nucleotides / Q000378:metabolism*; D017434:Protein Structure, Tertiary
chemical_list: D001426:Bacterial Proteins; D009711:Nucleotides; D006160:Guanosine Triphosphate; D034281:Dynamins