title: Magnetosomes are cell membrane invaginations organized by the actin-like protein MamK.
abstract: Magnetosomes are membranous bacterial organelles sharing many features of eukaryotic organelles. Using electron cryotomography, we found that magnetosomes are invaginations of the cell membrane flanked by a network of cytoskeletal filaments. The filaments appeared to be composed of MamK, a homolog of the bacterial actin-like protein MreB, which formed filaments in vivo. In a mamK deletion strain, the magnetosome-associated cytoskeleton was absent and individual magnetosomes were no longer organized into chains. Thus, it seems that prokaryotes can use cytoskeletal filaments to position organelles within the cell.
authors.affiliation: Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA. komeili@nature.berkeley.edu
authors.forename: Arash
authors.initials: A
authors.lastname: Komeili
authors.forename: Zhuo
authors.initials: Z
authors.lastname: Li
authors.forename: Dianne K
authors.initials: DK
authors.lastname: Newman
authors.forename: Grant J
authors.initials: GJ
authors.lastname: Jensen
mesh_terms: D000199:Actins / Q000737:chemistry; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D021961:Cell Membrane Structures / Q000737:chemistry / Q000502:physiology / Q000648:ultrastructure*; D020285:Cryoelectron Microscopy; D052203:Ferrosoferric Oxide; D042201:Magnetospirillum / Q000166:cytology / Q000235:genetics / Q000502:physiology / Q000648:ultrastructure*; D009154:Mutation; D015388:Organelles / Q000737:chemistry / Q000502:physiology / Q000648:ultrastructure*
chemical_list: D000199:Actins; D001426:Bacterial Proteins; D052203:Ferrosoferric Oxide