title: Motion of variable-length MreB filaments at the bacterial cell membrane influences cell morphology.
abstract: The maintenance of rod-cell shape in many bacteria depends on actin-like MreB proteins and several membrane proteins that interact with MreB. Using superresolution microscopy, we show that at 50-nm resolution, Bacillus subtilis MreB forms filamentous structures of length up to 3.4 μm underneath the cell membrane, which run at angles diverging up to 40° relative to the cell circumference. MreB from Escherichia coli forms at least 1.4-μm-long filaments. MreB filaments move along various tracks with a maximal speed of 85 nm/s, and the loss of ATPase activity leads to the formation of extended and static filaments. Suboptimal growth conditions lead to formation of patch-like structures rather than extended filaments. Coexpression of wild-type MreB with MreB mutated in the subunit interface leads to formation of shorter MreB filaments and a strong effect on cell shape, revealing a link between filament length and cell morphology. Thus MreB has an extended-filament architecture with the potential to position membrane proteins over long distances, whose localization in turn may affect the shape of the cell wall.
authors.affiliation: Mikrobiologie, Fakultät für Biologie, Universität Freiburg, 79104 Freiburg, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Reimold
authors.forename: Herve Joel
authors.initials: HJ
authors.lastname: Defeu Soufo
authors.forename: Felix
authors.initials: F
authors.lastname: Dempwolff
authors.forename: Peter L
authors.initials: PL
authors.lastname: Graumann
mesh_terms: D019943:Amino Acid Substitution; D001412:Bacillus subtilis / Q000166:cytology* / Q000378:metabolism / Q000648:ultrastructure; D001426:Bacterial Proteins / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism* / Q000648:ultrastructure; D004926:Escherichia coli / Q000166:cytology* / Q000378:metabolism / Q000648:ultrastructure; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D007700:Kinetics; D008164:Luminescent Proteins / Q000378:metabolism; D054730:Protein Interaction Domains and Motifs; D055503:Protein Multimerization; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D059008:Time-Lapse Imaging; D000097573:Red Fluorescent Protein
chemical_list: D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D008164:Luminescent Proteins; D011993:Recombinant Fusion Proteins; D000097573:Red Fluorescent Protein; C054562:yellow fluorescent protein, Bacteria; C078473:MreB protein, E coli