flagellum; pili; glycosylation; protein localisation; polarity; chemical genetics; capsule
Klöckner Anna, Bühl Henrike, Viollier Patrick, Henrichfreise Beate (2018), Biology of Chlamydia
, Springer International Publishing, Cham.
Bergé Matthieu, Viollier Patrick H. (2018), End-in-Sight: Cell Polarization by the Polygamic Organizer PopZ, in Trends in Microbiology
, 26(4), 363-375.
Mignolet Johann, Panis Gaël, Viollier Patrick H (2018), More than a Tad: spatiotemporal control of Caulobacter pili, in Current Opinion in Microbiology
, 42, 79-86.
Otten Christian, Brilli Matteo, Vollmer Waldemar, Viollier Patrick H., Salje Jeanne (2018), Peptidoglycan in obligate intracellular bacteriaPeptidoglycan in obligate intracellular bacteria, in Molecular Microbiology
, 107(2), 142-163.
Taylor James A., Panis Gaël, Viollier Patrick H., Marczynski Gregory T. (2017), A novel nucleoid-associated protein coordinates chromosome replication and chromosome partition, in Nucleic Acids Research
, 45(15), 8916-8929.
Hallez Régis, Delaby Marie, Sanselicio Stefano, Viollier Patrick H. (2017), Hit the right spots: cell cycle control by phosphorylated guanosines in alphaproteobacteria, in Nature Reviews Microbiology
, 15(3), 137-148.
Mignolet Johann, Holden Seamus, Bergé Matthieu, Panis Gaël, Eroglu Ezgi, Théraulaz Laurence, Manley Suliana, Viollier Patrick H (2016), Functional dichotomy and distinct nanoscale assemblies of a cell cycle-controlled bipolar zinc-finger regulator, in eLife
, 5, 1-21.
Bergé Matthieu, Campagne Sébastien, Mignolet Johann, Holden Seamus, Théraulaz Laurence, Manley Suliana, Allain Frédéric H-T, Viollier Patrick H (2016), Modularity and determinants of a (bi-)polarization control system from free-living and obligate intracellular bacteria, in eLife
, 5, 1-31.
Ardissone Silvia, Redder Peter, Russo Giancarlo, Frandi Antonio, Fumeaux Coralie, Patrignani Andrea, Schlapbach Ralph, Falquet Laurent, Viollier Patrick H. (2016), Cell Cycle Constraints and Environmental Control of Local DNA Hypomethylation in α-Proteobacteria, in PLOS Genetics
, 12(12), e1006499-e1006499.
Janakiraman Balaganesh, Mignolet Johann, Narayanan Sharath, Viollier Patrick H., Radhakrishnan Sunish Kumar (2016), In-phase oscillation of global regulons is orchestrated by a pole-specific organizer, in Proceedings of the National Academy of Sciences
, 113(44), 12550-12555.
Kirkpatrick Clare L., Martins Daniel, Redder Peter, Frandi Antonio, Mignolet Johann, Chapalay Julien Bortoli, Chambon Marc, Turcatti Gerardo, Viollier Patrick H. (2016), Growth control switch by a DNA-damage-inducible toxin–antitoxin system in Caulobacter crescentus, in Nature Microbiology
, 1(4), 16008-16008.
Sanselicio Stefano, Viollier Patrick H. (2015), Convergence of Alarmone and Cell Cycle Signaling from Trans -Encoded Sensory Domains, in mBio
, 6(5), 1-10.
Joshi Kamal Kishore, Bergé Matthieu, Radhakrishnan Sunish Kumar, Viollier Patrick Henri, Chien Peter (2015), An Adaptor Hierarchy Regulates Proteolysis during a Bacterial Cell Cycle, in Cell
, 163(2), 419-431.
Cells typically implement a myriad of molecular and macromolecular changes during cell cycle progression. The remodeling of cell surface structures and proteinaceous appendages during the bacterial cell cycle is still poorly understood. Arguably the best model system in which to study such structures and the underlying mechanism is the synchronizable a-proteobacterium Caulobacter crescentus (henceforth Caulobacter). This Gram-negative aquatic bacterium is non-pathogenic, but it divides asymmetrically and it features several surface structures whose functions can be conveniently probed using forward genetics. The power of such genetics alerted us to study new fundamental mechanisms and functions of three cell cycle-regulated structures: the polar flagellum, the polar pili and the capsule that are present at different times during the cell cycle. Our specific goals, framed in three ambitious and unrelated aims, are to:1) Explore how protein glycosylation controls flagellum assembly in Caulobacter via glycosyltransferase orthologs. 2) Dissect the cell polarization pathway that acts on pili.We will reconstitute the MapX/P polarization pathway and determine which known (or potentially unknown) pilus proteins are targeted by MapX/P in Caulobacter. 3) Use chemical-genetics to probe the protective functions of the capsule. We will screen for inhibitors of capsule production in an FDA-approved small molecule library and we will determine the genetic basis for the protection of the capsule from bacteriophages.Our studies on three cell cycle-regulated surface structures and the underlying mechanisms are important because they address fundamental concepts in eukaryotic and bacterial cell biology, including how protein function is regulated by glycosylation, how cell polarization is achieved and how exopolysaccharides fulfill protective roles. Additionally, these topics are of medical relevance as flagellin glycosylation, piliation and/or capsulation are required for virulence in many bacterial pathogens and many cousins of Caulobacter are plant, animal and/or human pathogens that also divide asymmetrically. Lastly compound screening experiments proposed here with Caulobacter make major strides in antibacterial drug discovery and may set the stage for a new combinatorial screening strategy.