title: Modularity and determinants of a (bi-)polarization control system from free-living and obligate intracellular bacteria.
abstract: Although free-living and obligate intracellular bacteria are both polarized it is unclear whether the underlying polarization mechanisms and effector proteins are conserved. Here we dissect at the cytological, functional and structural level a conserved polarization module from the free living α-proteobacteriumCaulobacter crescentusand an orthologous system from an obligate intracellular (rickettsial) pathogen. The NMR solution structure of the zinc-finger (ZnR) domain from the bifunctional and bipolar ZitP pilus assembly/motility regulator revealed conserved interaction determinants for PopZ, a bipolar matrix protein that anchors the ParB centromere-binding protein and other regulatory factors at the poles. We show that ZitP regulates cytokinesis and the localization of ParB and PopZ, targeting PopZ independently of the previously known binding sites for its client proteins. Through heterologous localization assays with rickettsial ZitP and PopZ orthologs, we document the shared ancestries, activities and structural determinants of a (bi-)polarization system encoded in free-living and obligate intracellular α-proteobacteria.
authors.affiliation: Department Microbiology and Molecular Medicine, Institute of Genetics and Genomics in Geneva, Faculty of Medicine, University of Geneva, Geneva, Switzerland.
authors.forename: Matthieu
authors.initials: M
authors.lastname: Bergé
authors.affiliation: Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule Zürich, Zürich, Switzerland.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Campagne
authors.affiliation: Department Microbiology and Molecular Medicine, Institute of Genetics and Genomics in Geneva, Faculty of Medicine, University of Geneva, Geneva, Switzerland.
authors.forename: Johann
authors.identifier: 0000-0002-3721-4307
authors.initials: J
authors.lastname: Mignolet
authors.affiliation: Laboratory of Experimental Biophysics, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
authors.forename: Seamus
authors.identifier: 0000-0002-7169-907X
authors.initials: S
authors.lastname: Holden
authors.affiliation: Department Microbiology and Molecular Medicine, Institute of Genetics and Genomics in Geneva, Faculty of Medicine, University of Geneva, Geneva, Switzerland.
authors.forename: Laurence
authors.initials: L
authors.lastname: Théraulaz
authors.affiliation: Laboratory of Experimental Biophysics, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
authors.forename: Suliana
authors.initials: S
authors.lastname: Manley
authors.affiliation: Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule Zürich, Zürich, Switzerland.
authors.forename: Frédéric H-T
authors.initials: FH
authors.lastname: Allain
authors.affiliation: Department Microbiology and Molecular Medicine, Institute of Genetics and Genomics in Geneva, Faculty of Medicine, University of Geneva, Geneva, Switzerland.
authors.forename: Patrick H
authors.identifier: 0000-0002-5249-9910
authors.initials: PH
authors.lastname: Viollier
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism*; D027682:Cation Transport Proteins / Q000378:metabolism*; D016935:Caulobacter crescentus / Q000201:enzymology* / Q000502:physiology; D016764:Cell Polarity; D048749:Cytokinesis; D011485:Protein Binding; D055503:Protein Multimerization; D021381:Protein Transport; D012281:Rickettsia / Q000201:enzymology* / Q000502:physiology
chemical_list: D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; D027682:Cation Transport Proteins
keywords: Caulobacter crescentus; E. coli; PopZ; Rhodobacter sphaeroides; Rickettsia massiliae; ZitP; cell biology; chromosomes; genes; polarity