title: Insights into type IV pilus biogenesis and dynamics from genetic analysis of a C-terminally tagged pilin: a role for O-linked glycosylation.
abstract: Type IV pili are surface organelles essential for pathogenicity of many Gram-negative bacteria. In Neisseria gonorrhoeae, the major subunit of type IV pili, PilE, is a target of its general O-linked glycosylation system. This system modifies a diverse set of periplasmic and extracellular gonococcal proteins with a variable set of glycans. Here we show that expression of a particular hexa-histidine-tagged PilE was associated with growth arrest. By studying intra- and extragenic suppressors, we found that this phenotype was dependent on pilus assembly and retraction. Based on these results, we developed a sensitive tool to identify factors with subtle effects on pilus dynamics. Using this approach, we found that glycan chain length has differential effects on the growth arrest that appears to be mediated at the level of pilin subunit-subunit interactions and bidirectional remodelling of pilin between its membrane-associated and assembled states. Gonococcal pilin glycosylation thus plays both an intracellular role in pilus dynamics and potential extracellular roles mediated through type IV pili. In addition to demonstrating the effect of glycosylation on pilus dynamics, the study provides a new way of identifying factors with less dramatic effects on processes involved in type IV pilus biogenesis.
authors.affiliation: Centre for Molecular Biology and Neuroscience             Department of Molecular Biosciences, University of Oslo, Oslo, Norway.
authors.forename: Åshild
authors.initials: Å
authors.lastname: Vik
authors.forename: Marina
authors.initials: M
authors.lastname: Aspholm
authors.forename: Jan Haug
authors.initials: JH
authors.lastname: Anonsen
authors.forename: Bente
authors.initials: B
authors.lastname: Børud
authors.forename: Norbert
authors.initials: N
authors.lastname: Roos
authors.forename: Michael
authors.initials: M
authors.lastname: Koomey
mesh_terms: D036781:Fimbriae Proteins / Q000235:genetics / Q000378:metabolism*; D010861:Fimbriae, Bacterial / Q000235:genetics / Q000378:metabolism*; D006031:Glycosylation; D009344:Neisseria gonorrhoeae / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D055503:Protein Multimerization
chemical_list: C074063:pilE protein, Neisseria gonorrhoeae; D036781:Fimbriae Proteins