title: ZipA is a MAP-Tau homolog and is essential for structural integrity of the cytokinetic FtsZ ring during bacterial cell division.
abstract: The first visible event in prokaryotic cell division is the assembly of the soluble, tubulin-like FtsZ GTPase into a membrane-associated cytokinetic ring that defines the division plane in bacterial and archaeal cells. In the temperature-sensitive ftsZ84 mutant of Escherichia coli, this ring assembly is impaired at the restrictive temperature causing lethal cell filamentation. Here I present genetic and morphological evidence that a 2-fold higher dosage of the division gene zipA suppresses thermosensitivity of the ftsZ84 mutant by stabilizing the labile FtsZ84 ring structure in vivo. I demonstrate that purified ZipA promotes and stabilizes protofilament assembly of both FtsZ and FtsZ84 in vitro and cosediments with the protofilaments. Furthermore, ZipA organizes FtsZ protofilaments into arrays of long bundles or sheets that probably represent the physiological organization of the FtsZ ring in bacterial cells. The N-terminal cytoplasmic domain of membrane-anchored ZipA contains sequence elements that resemble the microtubule-binding signature motifs in eukaryotic Tau, MAP2 and MAP4 proteins. It is postulated that the MAP-Tau-homologous motifs in ZipA mediate its binding to FtsZ, and that FtsZ-ZipA interaction represents an ancient prototype of the protein-protein interaction that enables MAPs to suppress microtubule catastrophe and/or to promote rescue.
authors.affiliation: Department of Molecular Biology and Microbiology, Tufts University School of Medicine, 136 Harrison Avenue, Boston, MA 02111, USA. draychau@opal.tufts.edu
authors.forename: D
authors.initials: D
authors.lastname: RayChaudhuri
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D002455:Cell Division / Q000235:genetics; D003598:Cytoskeletal Proteins; D004926:Escherichia coli; D029968:Escherichia coli Proteins; D018628:Gene Dosage; D006160:Guanosine Triphosphate / Q000378:metabolism; D006358:Hot Temperature; D008869:Microtubule-Associated Proteins / Q000737:chemistry; D008969:Molecular Sequence Data; D009154:Mutation; D011485:Protein Binding; D011994:Recombinant Proteins / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D016875:tau Proteins / Q000737:chemistry
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D003598:Cytoskeletal Proteins; D029968:Escherichia coli Proteins; C071525:FtsZ protein, Bacteria; D008869:Microtubule-Associated Proteins; D011994:Recombinant Proteins; C103795:ZipA protein, E coli; D016875:tau Proteins; D006160:Guanosine Triphosphate