title: Bacterial birth scar proteins mark future flagellum assembly site.
abstract: Many prokaryotic protein complexes underlie polar asymmetry. In Caulobacter crescentus, a flagellum is built exclusively at the pole that arose from the previous cell division. The basis for this pole specificity is unclear but could involve a cytokinetic birth scar that marks the newborn pole as the flagellum assembly site. We identified two developmental proteins, TipN and TipF, which localize to the division septum and the newborn pole after division. We show that septal localization of TipN/F depends on cytokinesis. Moreover, TipF, a c-di-GMP phosphodiesterase homolog, is a flagellum assembly factor that relies on TipN for proper positioning. In the absence of TipN, flagella are assembled at ectopic locations, and TipF is mislocalized to such sites. Thus TipN and TipF establish a link between bacterial cytokinesis and polar asymmetry, demonstrating that division does indeed leave a positional mark in its wake to direct the biogenesis of a polar organelle.
authors.affiliation: Department of Molecular Biology and Microbiology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA.
authors.forename: Edgar
authors.initials: E
authors.lastname: Huitema
authors.forename: Sean
authors.initials: S
authors.lastname: Pritchard
authors.forename: David
authors.initials: D
authors.lastname: Matteson
authors.forename: Sunish Kumar
authors.initials: SK
authors.lastname: Radhakrishnan
authors.forename: Patrick H
authors.initials: PH
authors.lastname: Viollier
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D016935:Caulobacter crescentus / Q000166:cytology* / Q000378:metabolism; D002465:Cell Movement; D016764:Cell Polarity; D048749:Cytokinesis / Q000502:physiology*; D003598:Cytoskeletal Proteins / Q000378:metabolism; D005407:Flagella / Q000378:metabolism* / Q000648:ultrastructure; D009154:Mutation; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D003598:Cytoskeletal Proteins; C071525:FtsZ protein, Bacteria; D011993:Recombinant Fusion Proteins