title: CetZ tubulin-like proteins control archaeal cell shape.
abstract: Tubulin is a major component of the eukaryotic cytoskeleton, controlling cell shape, structure and dynamics, whereas its bacterial homologue FtsZ establishes the cytokinetic ring that constricts during cell division. How such different roles of tubulin and FtsZ evolved is unknown. Studying Archaea may provide clues as these organisms share characteristics with Eukarya and Bacteria. Here we report the structure and function of proteins from a distinct family related to tubulin and FtsZ, named CetZ, which co-exists with FtsZ in many archaea. CetZ X-ray crystal structures showed the FtsZ/tubulin superfamily fold, and one crystal form contained sheets of protofilaments, suggesting a structural role. However, inactivation of CetZ proteins in Haloferax volcanii did not affect cell division. Instead, CetZ1 was required for differentiation of the irregular plate-shaped cells into a rod-shaped cell type that was essential for normal swimming motility. CetZ1 formed dynamic cytoskeletal structures in vivo, relating to its capacity to remodel the cell envelope and direct rod formation. CetZ2 was also implicated in H. volcanii cell shape control. Our findings expand the known roles of the FtsZ/tubulin superfamily to include archaeal cell shape dynamics, suggesting that a cytoskeletal role might predate eukaryotic cell evolution, and they support the premise that a major function of the microbial rod shape is to facilitate swimming.
authors.affiliation: 1] Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK [2] The ithree institute, University of Technology Sydney, New South Wales 2007, Australia.
authors.forename: Iain G
authors.initials: IG
authors.lastname: Duggin
authors.affiliation: Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK.
authors.forename: Christopher H S
authors.initials: CH
authors.lastname: Aylett
authors.affiliation: 1] The ithree institute, University of Technology Sydney, New South Wales 2007, Australia [2] School of Physics, University of New South Wales, Sydney, New South Wales 2052, Australia.
authors.forename: James C
authors.initials: JC
authors.lastname: Walsh
authors.affiliation: Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK.
authors.forename: Katharine A
authors.initials: KA
authors.lastname: Michie
authors.affiliation: Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK.
authors.forename: Qing
authors.initials: Q
authors.lastname: Wang
authors.affiliation: The ithree institute, University of Technology Sydney, New South Wales 2007, Australia.
authors.forename: Lynne
authors.initials: L
authors.lastname: Turnbull
authors.affiliation: The ithree institute, University of Technology Sydney, New South Wales 2007, Australia.
authors.forename: Emma M
authors.initials: EM
authors.lastname: Dawson
authors.affiliation: The ithree institute, University of Technology Sydney, New South Wales 2007, Australia.
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: Harry
authors.affiliation: The ithree institute, University of Technology Sydney, New South Wales 2007, Australia.
authors.forename: Cynthia B
authors.initials: CB
authors.lastname: Whitchurch
authors.affiliation: Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK.
authors.forename: Linda A
authors.initials: LA
authors.lastname: Amos
authors.affiliation: Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK.
authors.forename: Jan
authors.initials: J
authors.lastname: Löwe
mesh_terms: D000595:Amino Acid Sequence; D019843:Archaeal Proteins / Q000737:chemistry* / Q000378:metabolism*; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism; D002455:Cell Division; D002462:Cell Membrane / Q000378:metabolism; D048430:Cell Shape; D018360:Crystallography, X-Ray; D003598:Cytoskeletal Proteins / Q000737:chemistry / Q000378:metabolism; D019622:Haloferax volcanii / Q000166:cytology* / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009068:Movement; D014404:Tubulin / Q000737:chemistry / Q000378:metabolism*
chemical_list: D019843:Archaeal Proteins; D001426:Bacterial Proteins; D003598:Cytoskeletal Proteins; C071525:FtsZ protein, Bacteria; D014404:Tubulin