title: Molecular Interaction and Cellular Location of RecA and CheW Proteins inSalmonella entericaduring SOS Response and Their Implication in Swarming.
abstract: In addition to its role in DNA damage repair and recombination, the RecA protein, through its interaction with CheW, is involved in swarming motility, a form of flagella-dependent movement across surfaces. In order to better understand how SOS response modulates swarming, in this work the location of RecA and CheW proteins within the swarming cells has been studied by using super-resolution microscopy. Further, and afterin silicodocking studies, the specific RecA and CheW regions associated with the RecA-CheW interaction have also been confirmed by site-directed mutagenesis and immunoprecipitation techniques. Our results point out that the CheW distribution changes, from the cell poles to foci distributed in a helical pattern along the cell axis when SOS response is activated or RecA protein is overexpressed. In this situation, the CheW presents the same subcellular location as that of RecA, pointing out that the previously described RecA storage structures may be modulators of swarming motility. Data reported herein not only confirmed that the RecA-CheW pair is essential for swarming motility but it is directly involved in the CheW distribution change associated to SOS response activation. A model explaining not only the mechanism by which DNA damage modulates swarming but also how both the lack and the excess of RecA protein impair this motility is proposed.
authors.affiliation: Department de Genètica i de Microbiologia, Universitat Autònoma de Barcelona Cerdanyola del Vallès, Spain.
authors.forename: Oihane
authors.initials: O
authors.lastname: Irazoki
authors.affiliation: Department de Genètica i de Microbiologia, Universitat Autònoma de Barcelona Cerdanyola del Vallès, Spain.
authors.forename: Jesús
authors.initials: J
authors.lastname: Aranda
authors.affiliation: Advanced Light Microscopy Unit, Center for Genomic Regulation Barcelona, Spain.
authors.forename: Timo
authors.initials: T
authors.lastname: Zimmermann
authors.affiliation: Department de Genètica i de Microbiologia, Universitat Autònoma de Barcelona Cerdanyola del Vallès, Spain.
authors.forename: Susana
authors.initials: S
authors.lastname: Campoy
authors.affiliation: Department de Genètica i de Microbiologia, Universitat Autònoma de Barcelona Cerdanyola del Vallès, Spain.
authors.forename: Jordi
authors.initials: J
authors.lastname: Barbé
keywords: 3D-STED; CheW; RecA; SOS response; chemoreceptor polar arrays; chemosensory cluster assembly; swarming