title: Binding of the RNA chaperone Hfq to the type IV pilus base is crucial for its function in Synechocystis sp. PCC 6803.
abstract: The bacterial RNA-binding protein Hfq functions in post-transcriptional regulation of gene expression. There is evidence in a range of bacteria for specific subcellular localization of Hfq; however, the mechanism and role of Hfq localization remain unclear. Cyanobacteria harbour a subfamily of Hfq that is structurally conserved but exhibits divergent RNA binding sites. Mutational analysis in the cyanobacterium Synechocystis sp. PCC 6803 revealed that several conserved amino acids on the proximal side of the Hfq hexamer are crucial not only for Hfq-dependent RNA accumulation but also for phototaxis, the latter of which depends on type IV pili. Co-immunoprecipitation and yeast two-hybrid analysis show that the secretion ATPase PilB1 (a component of the type IV pilus base) is an interaction partner of Hfq. Fluorescence microscopy revealed that Hfq is localized to the cytoplasmic membrane in a PilB1-dependent manner. Concomitantly, Hfq-dependent RNA accumulation is abrogated in a ΔpilB1 mutant, indicating that localization to the pilus base via interaction with PilB1 is essential for Hfq function in cyanobacteria.
authors.affiliation: Molekulare Genetik, Fakultät für Biologie, Albert-Ludwigs-Universität Freiburg, Freiburg, D-79104, Germany.
authors.forename: Nils
authors.initials: N
authors.lastname: Schuergers
authors.forename: Ulrike
authors.initials: U
authors.lastname: Ruppert
authors.forename: Satoru
authors.initials: S
authors.lastname: Watanabe
authors.forename: Dennis J
authors.initials: DJ
authors.lastname: Nürnberg
authors.forename: Günter
authors.initials: G
authors.lastname: Lochnit
authors.forename: Dennis
authors.initials: D
authors.lastname: Dienst
authors.forename: Conrad W
authors.initials: CW
authors.lastname: Mullineaux
authors.forename: Annegret
authors.initials: A
authors.lastname: Wilde
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism*; D058947:Bacterial Secretion Systems; D004252:DNA Mutational Analysis; D010861:Fimbriae, Bacterial / Q000502:physiology*; D015964:Gene Expression Regulation, Bacterial; D035001:Host Factor 1 Protein / Q000235:genetics / Q000378:metabolism*; D047468:Immunoprecipitation; D010088:Oxidoreductases / Q000378:metabolism*; D011485:Protein Binding; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D046939:Synechocystis / Q000235:genetics* / Q000378:metabolism; D020798:Two-Hybrid System Techniques
chemical_list: D001426:Bacterial Proteins; D058947:Bacterial Secretion Systems; D035001:Host Factor 1 Protein; D016601:RNA-Binding Proteins; D010088:Oxidoreductases; C068255:pilB protein, Bacteria; D000251:Adenosine Triphosphatases