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Identification of Icm protein complexes that play distinct roles in the biogenesis of an organelle permissive for Legionella pneumophila intracellular growth
Author(s) -
Coers Jörn,
Kagan Jonathan C.,
Matthews Miguelina,
Nagai Hiroki,
Zuckman Deborah M.,
Roy Craig R.
Publication year - 2000
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1046/j.1365-2958.2000.02176.x
Subject(s) - biology , legionella pneumophila , phagosome , microbiology and biotechnology , organelle , biogenesis , virulence , gene , secretion , transport protein , organelle biogenesis , intracellular , genetics , bacteria , biochemistry
Legionella pneumophila is a bacterial pathogen that can enter the human lung and grow inside alveolar macrophages. To grow within phagocytic host cells, the bacteria must create a specialized organelle that restricts fusion with lysosomes. Biogenesis of this replicative organelle is controlled by 24 dot and icm genes, which encode a type IV‐related transport apparatus. To understand how this transporter functions, isogenic L. pneumophila dot and icm mutants were characterized, and three distinct phenotypic categories were identified. Our data show that, in addition to genes that encode the core Dot/Icm transport apparatus, subsets of genes are required for pore formation and modulation of phagosome trafficking. To understand activities required for virulence at a molecular level, we investigated protein–protein interactions. Specific interactions between different Icm proteins were detected by yeast two‐hybrid and gel overlay analysis. These data support a model in which the IcmQ–IcmR complex regulates the formation of a translocation channel that delivers proteins into host cells, and the IcmS–IcmW complex is required for export of virulence determinants that modulate phagosome trafficking.