Mechanisms of Intracellular Survival and Replication of Legionella pneumophila
Tamara O'Conner, Matthew Heidtman and Ralph R. Isberg
from: Legionella: Molecular Microbiology (Edited by: Klaus Heuner and Michele Swanson). Caister Academic Press, U.K. (2008)
Abstract
Upon uptake by phagocytic cells the Legionella containing phagosome (LCV) evades targeting to and degradation by the endocytic pathway. Instead, mitochondria and early secretory vesicles are rapidly recruited to the LCV. Over a period of several hours, the LCV becomes studded with ribosomes and resembles an ER-like compartment. Within this organelle L. pneumophila is able to replicate to high numbers. Intracellular growth of L. pneumophila is dependent on the dot/icm genes. Many of the Dot/Icm proteins assemble into a large membrane-spanning complex that enables the delivery of bacterial proteins into the host cell cytosol. These translocated substrates are thought to modulate a variety of host cell processes to create an intracellular environment permissive for bacterial replication. The functions of most of these substrates are unknown, although at least some of them are known to modulate host cell vesicle trafficking and anti-apoptotic signaling pathways. Recent studies have sought to identify host cell processes important for L. pneumophila intracellular replication. The input of multiple host cell vesicle trafficking pathways, the ERAD system, anti-apoptotic signaling, autophagy, and host cell lipid metabolism all appear to be important to varying extents for efficient intracellular growth of L. pneumophila read more ...
