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Virulence. 2013 May 15;4(4):307-14. doi: 10.4161/viru.24290. Epub 2013 Mar 27.

Cellular microbiology and molecular ecology of Legionella-amoeba interaction.

Author information

1
Department of Microbiology and Immunology, College of Medicine, University of Louisville, Louisville, KY, USA.

Abstract

Legionella pneumophila is an aquatic organism that interacts with amoebae and ciliated protozoa as the natural hosts, and this interaction plays a central role in bacterial ecology and infectivity. Upon transmission to humans, L. pneumophila infect and replicate within alveolar macrophages causing pneumonia. Intracellular proliferation of L. pneumophila within the two evolutionarily distant hosts is facilitated by bacterial exploitation of evolutionarily conserved host processes that are targeted by bacterial protein effectors injected into the host cell by the Dot/Icm type VIB translocation system. Although cysteine is semi-essential for humans and essential for amoeba, it is a metabolically favorable source of carbon and energy generation by L. pneumophila. To counteract host limitation of cysteine, L. pneumophila utilizes the AnkB Dot/Icm-translocated F-box effector to promote host proteasomal degradation of polyubiquitinated proteins within amoebae and human cells. Evidence indicates ankB and other Dot/Icm-translocated effector genes have been acquired through inter-kingdom horizontal gene transfer.

KEYWORDS:

Ankyrin; Ankyrin B; Dot/Icm; Legionnaire; RelA; SpoT; cysteine; effectors AnkB; farnesylation; pneumophila; polyubiquitin; ppGpp; prenylation; proteasomes

PMID:
23535283
PMCID:
PMC3710333
DOI:
10.4161/viru.24290
[Indexed for MEDLINE]
Free PMC Article

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