title: The N-Terminal GYPSY Motif Is Required for Pilin-Specific Sortase SrtC1 Functionality in Lactobacillus rhamnosus Strain GG.
abstract: Predominantly identified in pathogenic Gram-positive bacteria, sortase-dependent pili are also found in commensal species, such as the probiotic-marketed strain Lactobacillus rhamnosus strain GG. Pili are typically associated with host colonization, immune signalling and biofilm formation. Comparative analysis of the N-terminal domains of pilin-specific sortases from various piliated Gram-positive bacteria identified a conserved motif, called GYPSY, within the signal sequence. We investigated the function and role of the GYPSY residues by directed mutagenesis in homologous (rod-shaped) and heterologous (coccoid-shaped) expression systems for pilus formation. Substitutions of some of the GYPSY residues, and more specifically the proline residue, were found to have a direct impact on the degree of piliation of Lb. rhamnosus GG. The present findings uncover a new signalling element involved in the functionality of pilin-specific sortases controlling the pilus biogenesis of Lb. rhamnosus GG and related piliated Gram-positive species.
authors.affiliation: Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland.
authors.forename: François P
authors.initials: FP
authors.lastname: Douillard
authors.affiliation: Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland.
authors.forename: Pia
authors.initials: P
authors.lastname: Rasinkangas
authors.affiliation: Research Programs Unit Immunobiology, Department of Bacteriology and Immunology, University of Helsinki, Helsinki, Finland.
authors.forename: Arnab
authors.initials: A
authors.lastname: Bhattacharjee
authors.affiliation: Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland.
authors.forename: Airi
authors.initials: A
authors.lastname: Palva
authors.affiliation: Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland.|Research Programs Unit Immunobiology, Department of Bacteriology and Immunology, University of Helsinki, Helsinki, Finland.|Laboratory of Microbiology, Wageningen University, Wageningen, The Netherlands.
authors.forename: Willem M
authors.initials: WM
authors.lastname: de Vos
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000378:metabolism*; D036781:Fimbriae Proteins / Q000378:metabolism*; D052201:Lacticaseibacillus rhamnosus / Q000378:metabolism*; D021382:Protein Sorting Signals; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment
chemical_list: D001426:Bacterial Proteins; D021382:Protein Sorting Signals; D036781:Fimbriae Proteins