Journal article
Legionella pneumophila DotU and IcmF Are Required for Stability of the Dot/Icm Complex
Infection and immunity, Vol.72(10), pp.5983-5992
10/01/2004
DOI: 10.1128/IAI.72.10.5983-5992.2004
PMCID: PMC517559
PMID: 15385502
Abstract
Legionella pneumophila
utilizes a type IV secretion system (T4SS) encoded by 26
dot
/
icm
genes to replicate inside host cells and cause disease. In contrast to all other
L. pneumophila dot/icm
genes,
dotU
and
icmF
have homologs in a wide variety of gram-negative bacteria, none of which possess a T4SS. Instead,
dotU
and
icmF
orthologs are linked to a locus encoding a conserved cluster of proteins designated IcmF-associated homologous proteins, which has been proposed to constitute a novel cell surface structure. We show here that
dotU
is partially required for
L. pneumophila
intracellular growth, similar to the known requirement for
icmF
. In addition, we show that
dotU
and
icmF
are necessary for optimal plasmid transfer and sodium sensitivity, two additional phenotypes associated with a functional Dot/Icm complex. We found that these effects are due to the destabilization of the T4SS at the transition into the stationary phase, the point at which
L. pneumophila
becomes virulent. Specifically, three Dot proteins (DotH, DotG, and DotF) exhibit decreased stability in a Δ
dotU
Δ
icmF
strain. Furthermore, overexpression of just one of these proteins, DotH, is sufficient to suppress the intracellular growth defect of the Δ
dotU
Δ
icmF
mutant. This suggests a model where the DotU and IcmF proteins serve to prevent DotH degradation and therefore function to stabilize the
L. pneumophila
T4SS. Due to their wide distribution among bacterial species and their genetic linkage to known or predicted cell surface structures, we propose that this function in complex stabilization may be broadly conserved.
Details
- Title: Subtitle
- Legionella pneumophila DotU and IcmF Are Required for Stability of the Dot/Icm Complex
- Creators
- Jessica A. Sexton - Washington University in St. LouisJennifer L. Miller - Washington University in St. LouisAki Yoneda - Washington University in St. LouisThomas E. Kehl-Fie - Washington University in St. LouisJoseph P. Vogel - Washington University in St. Louis
- Resource Type
- Journal article
- Publication Details
- Infection and immunity, Vol.72(10), pp.5983-5992
- Publisher
- American Society for Microbiology
- DOI
- 10.1128/IAI.72.10.5983-5992.2004
- PMID
- 15385502
- PMCID
- PMC517559
- ISSN
- 0019-9567
- eISSN
- 1098-5522
- Language
- English
- Date published
- 10/01/2004
- Academic Unit
- Microbiology and Immunology
- Record Identifier
- 9984618644202771
Metrics
7 Record Views