title: Direct membrane binding by bacterial actin MreB.
abstract: Bacterial actin MreB is one of the key components of the bacterial cytoskeleton. It assembles into short filaments that lie just underneath the membrane and organize the cell wall synthesis machinery. Here we show that MreB from both T. maritima and E. coli binds directly to cell membranes. This function is essential for cell shape determination in E. coli and is proposed to be a general property of many, if not all, MreBs. We demonstrate that membrane binding is mediated by a membrane insertion loop in TmMreB and by an N-terminal amphipathic helix in EcMreB and show that purified TmMreB assembles into double filaments on a membrane surface that can induce curvature. This, the first example of a membrane-binding actin filament, prompts a fundamental rethink of the structure and dynamics of MreB filaments within cells.
authors.affiliation: MRC Laboratory of Molecular Biology, Cambridge, UK.
authors.forename: Jeanne
authors.initials: J
authors.lastname: Salje
authors.forename: Fusinita
authors.initials: F
authors.lastname: van den Ent
authors.forename: Piet
authors.initials: P
authors.lastname: de Boer
authors.forename: Jan
authors.initials: J
authors.lastname: Löwe
mesh_terms: D008841:Actin Cytoskeleton / Q000737:chemistry / Q000378:metabolism; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology; D002462:Cell Membrane / Q000378:metabolism* / Q000648:ultrastructure; D003598:Cytoskeletal Proteins / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology; D004926:Escherichia coli / Q000378:metabolism* / Q000648:ultrastructure; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology; D049452:Green Fluorescent Proteins / Q000032:analysis; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D020124:Thermotoga maritima / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D001426:Bacterial Proteins; D003598:Cytoskeletal Proteins; D029968:Escherichia coli Proteins; D049452:Green Fluorescent Proteins