Format

Send to

Choose Destination
See comment in PubMed Commons below
J Bacteriol. 2008 Nov;190(21):6961-9. doi: 10.1128/JB.00996-08. Epub 2008 Sep 5.

PilF is an outer membrane lipoprotein required for multimerization and localization of the Pseudomonas aeruginosa Type IV pilus secretin.

Author information

  • 1Department of Biochemistry, University of Toronto, Program in Molecular Structure and Function, The Hospital for Sick Children, 555 University Avenue, Toronto M5G 1X8, ON, Canada.

Abstract

Type IV pili (T4P) are retractile appendages that contribute to the virulence of bacterial pathogens. PilF is a Pseudomonas aeruginosa lipoprotein that is essential for T4P biogenesis. Phenotypic characterization of a pilF mutant confirmed that T4P-mediated functions are abrogated: T4P were no longer present on the cell surface, twitching motility was abolished, and the mutant was resistant to infection by T4P retraction-dependent bacteriophage. The results of cellular fractionation studies indicated that PilF is the outer membrane pilotin required for the localization and multimerization of the secretin, PilQ. Mutation of the putative PilF lipidation site untethered the protein from the outer membrane, causing secretin assembly in both inner and outer membranes. T4P-mediated twitching motility and bacteriophage susceptibility were moderately decreased in the lipidation site mutant, while cell surface piliation was substantially reduced. The tethering of PilF to the outer membrane promotes the correct localization of PilQ and appears to be required for the formation of stable T4P. Our 2.0-A structure of PilF revealed a superhelical arrangement of six tetratricopeptide protein-protein interaction motifs that may mediate the contacts with PilQ during secretin assembly. An alignment of pseudomonad PilF sequences revealed three highly conserved surfaces that may be involved in PilF function.

PMID:
18776008
PMCID:
PMC2580691
DOI:
10.1128/JB.00996-08
[PubMed - indexed for MEDLINE]
Free PMC Article
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Support Center