Bactofilins, a ubiquitous class of cytoskeletal proteins mediating polar localization of a cell wall synthase in Caulobacter crescentus.
The cytoskeleton has a key function in the temporal and spatial organization of both prokaryotic and eukaryotic cells. Here, we report the identification of a new class of polymer-forming proteins, termed bactofilins, that are widely conserved among bacteria. In Caulobacter crescentus, two bactofilin paralogues cooperate to form a sheet-like structure lining the cytoplasmic membrane in proximity of the stalked cell pole. These assemblies mediate polar localization of a peptidoglycan synthase involved in stalk morphogenesis, thus complementing the function of the actin-like cytoskeleton and the cell division machinery in the regulation of cell wall biogenesis. In other bacteria, bactofilins can establish rod-shaped filaments or associate with the cell division apparatus, indicating considerable structural and functional flexibility. Bactofilins polymerize spontaneously in the absence of additional cofactors in vitro, forming stable ribbon- or rod-like filament bundles. Our results suggest that these structures have evolved as an alternative to intermediate filaments, serving as versatile molecular scaffolds in a variety of cellular pathways.
Kühn
Juliane
J
Max Planck Institute for Terrestrial Microbiology, Marburg, Germany.
Briegel
Ariane
A
Mörschel
Erhard
E
Kahnt
Jörg
J
Leser
Katja
K
Wick
Stephanie
S
Jensen
Grant J
GJ
Thanbichler
Martin
M
D001426:Bacterial Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D016935:Caulobacter crescentus / Q000737:chemistry / Q000166:cytology* / Q000378:metabolism; D002473:Cell Wall / Q000378:metabolism*; D017124:Conserved Sequence; D003598:Cytoskeletal Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D003599:Cytoskeleton / Q000737:chemistry / Q000378:metabolism; D046915:Penicillin-Binding Proteins / Q000032:analysis / Q000378:metabolism*; D010802:Phylogeny; D021381:Protein Transport
D001426:Bacterial Proteins; D003598:Cytoskeletal Proteins; D046915:Penicillin-Binding Proteins